EPA
600/R—96/077
United States NHEERL E PAI600R-96/077
Environmental Protection Western Ecology Division June 1996
Agency Corvallis OR 97333
Research and Development
EPA LEVEL III AND IV ECOREGIONS Or
PENNSYLVANIA AND THE BLUE RIDGE
MOUNTAINS, THE CENTRAL APPALACHIAN
RIDGE AND VALLEY, AND THE CENTRAL
APPALACHIANS OF VIRGINIA, WEST
VIRGINIA AND MARYLAND
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LEVEL HI AND IV ECOREGIONS OF PENNSYLVANIA AND THE BLUE RIDGE
MOUNTAINS, THE CENTRAL APPALACHIAN RIDGE AND VALLEY,
AND THE CENTRAL APPALACHIANS OF VIRGINIA, WEST VIRGINIA,
AND MARYLAND
by
AlanJ Woods'
James M Omemik2
Douglas D Brown3
ChnsW Kiilsgaard4
EPA/600/R-96/077
June, 1996
U S Environmental Protection Agency
National Health and Environmental Effects Laboratory
200 SW 35th Street
Corvallis, Oregon 97333
The information in this document has been funded wholly by
the US Environmental Protection Agency It has been subjected to the
Agency's peer and administrative review, and it has been approved for
publication as an EPA document
'Dynamac Corporation
U S EPA National Health and Environmental Effects Laboratory
200 SW 35th Street
Corvallis, Oregon 97333
2U S Environmental Protection Agency
National Health and Environmental Effects Laboratory
200 SW 35th Street
Corvalhs, Oregon 97333
'US Forest Service
Rocky Mountain Forest and Range Experiment Station
240 Prospect Rd
Ft Collins, Colorado 80526
''Oregon Department of Fish and Wildlife
7118 NE Vandenberg Av
Corvalhs, Oregon 97330
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TABLE OF CONTENTS
Section Page
BACKGROUND 1
METHODS 3
REGIONAL DESCRIPTIONS.. 4
Northeastern Highlands (58) 4
Reading Prong (58h) .. 4
Northern Appalachian Plateau and Uplands (60) . . .. 4
Glaciated Low Plateau (60a) 5
Northeastern Uplands (60b) 6
Ene/Ontano Hills and Lake Plain (61) .. 7
Erie Lake Plain (61 a) 8
Mosquito Creek-Pymatuning Lowlands (61b) 9
Low Lime Till Plain (61c) 10
North Central Appalachians (62) 11
Pocono High Plateau (62a) 11
Low Poconos (62b) 13
Glaciated Allegheny High Plateau (62c) 14
Unglaciated Allegheny High Plateau (62d) 14
Low Catskills (62e) 16
Middle Atlantic Coastal Plam (63) 16
Delaware River Terraces and Uplands (63a) 16
Northern Piedmont Ecoregion (64) 17
Triassic Lowlands (64a) 18
Diabase and Conglomerate Uplands (64b) 19
Piedmont Uplands (64c) 19
Piedmont Limestone/Dolomite Lowlands (64d) 20
Blue Ridge Mountains (66) 21
Northern Igneous Ridges (66a) 22
Northern Sedimentary and Metasedimentary Ridges (66b) 23
Interior Plateau (66c) 23
Southern Igneous Ridges and Mountams (66d) 23
Southern Sedimentary Ridges (66e) 24
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TABLE OF CONTENTS (Continued)
Ridge and Valley (67) 24
Northern Limestone/Dolomite Valleys (67a) 26
Northern Shale Valleys (67b) 26
Northern Sandstone Ridges (67c) 27
Northern Dissected Ridges (67d) 27
Anthracite (67e) 28
Southern Limestone/Dolomite Valleys and Low Rolling Hills (670 28
Southern Shale Valleys (67g) 29
Southern Sandstone Ridges (6Th) 29
Southern Dissected Ridges (67i) 30
Central Appalachians (69) 30
Forested Hills and Mountains (69a) 31
Uplands and Valleys of Mixed Land Use (69b) 32
Greenbrier Karst (69c) 33
Cumberland Mountains (69d) . .. . 34
Western Allegheny Plateau (70) 34
Perrnian Hills (70a) 35
Monongahela Transition Zone (70b) 36
Pittsburgh Low Plateau (70c) 36
REFERENCES 38
APPENDIX 1: Ecoregion summary data 47
FIGURE 1. Ecoregions of Permsylvania and the Blue Ridge 5()
Mountains, Ridge and Valley, and Central Appalachians of EPA
Region 3
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LEVEL III AND IV ECOREGIONS OF PENNSYLVANIA AND
THE BLUE RIDGE MOUNTAINS, THE RIDGE AND VALLEY, AND THE CENTRAL
APPALACHIANS OF VIRGINIA, WEST VIRGINIA, AND MARYLAND
BACKGROUND
Environmental resources research, assessment, monitonng, and, ultimately, management
typically require appropriate spatial structures. Ecoregion frameworks are well suited to these
purposes.
Ecoregions are defined as areas of relative homogeneity in ecological systems and their
components. Factors associated with spatial differences in the quality and quantity of
ecosystem components, including soils, vegetation, climate, geology, and physiography, are
relatively homogeneous within an ecoregion. Ecoregions separate different patterns of human
stresses on the environment and different patterns m the existing and attainable quality of
environmental resources. They have proven to be an effective aid for inventorying and assessmg
national and regional environmental resources, for setting regional resource management goals, and
for developing biological criteria and water quality standards (Environment Canada, 1989; Gallant
and others, 1989; Hughes and others, 1990, 1994; Hughes, 1989b; U S. Environmental Protection
Agency, Science Advisory Board 1991; Warry and Hanau, 1993),
Ecoregion frameworks have been developed for the United States (Bailey, 1976, 1983;
Bailey and others, 1994; Omernik, 1987, 1995a; U S. Environmental Protection Agency, 1996),
Canada (Ecological Stratification Working Group, 1995; Wiken, 1986), New Zealand (Biggs and
others, 1990), the Netherlands (Klijn, 1994), and other countries. North Amencan ecoregion
frameworks have evolved considerably in recent years (Bailey, 1995; Bailey and others, 1985;
Omernik, 1995a; Omernik and Gallant, 1990). The first compilation of ecoregions in the
conterminous United States by the U.S Environmental Protection Agency (U.S. EPA) was
performed at a relatively cursory scale of 1:3,168,000 and was published at a smaller scale of
1:7,500,000 (Omemik, 1987). Subsequently, this ecoregion framework was revised and made
hierarchical (U S. Environmental Protection Agency, 1996). It was also expanded to include
Alaska (Gallant and others, 1995) and North America (Omemik, 1 995b)
The approach we have used to compile ecoregion maps is based on the premise that
ecological regions can be identified by analyzing the patterns and composition of biotic and
abiotic phenomena that affect or reflect differences in ecosystem quality and integnty (Wiken,
1986; Omernik, 1995a). These phenomena include geology, physiography, vegetation, climate,
soils, land use, wildhfe, and hydrology. We do not begin by treating any one phenomena with
more weight than any other. Rather, we look for patterns of coincidence between geographic
phenomena that cause or reflect differences in ecosystem quality, health and integrity. The
relative importance of each characteristic varies from one ecological region to another, regardless
of the hierarchical level. Because of possible confusion with other meanings of terms for different
levels of ecological regions, a Roman numeral classification scheme has been adopted for this
effort. Level I is the coarsest level, dividing North America into 15 ecological regions. At level II,
the continent is subdivided into 52 classes, and at level HI, the continental United States contains
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98 ecoregions. Level IV ecological regions are further subdivisions of level II I units and are
typically the finest that can be readily compiled from 1:250,000 scale bases. The exact number
of ecological regions at each hierarchical level is still changing slightly as the framework undergoes
development at the international, national, and local levels.
The ecoregions defined by Omernik (1987) have proved to be useful for stratifying
streams in Arkansas (Rohm and others, 1987), Nebraska (Bazata, 1991), Ohio (Larsen and
others, 1986), Oregon (Hughes and others, 1987; Whittier and others, 1988), Washington
(Plotrnkoff 1992), and Wisconsin (Lyons, 1989). Omernik’s ecoregion map (1987) was used to
set water quality standards in Arkansas (Arkansas Department of Pollution Control and Ecology,
1988), to identify lake management goals in Minnesota (Heiskary and Wilson, 1989), and to
develop biological criteria in Ohio (Ohio EPA, 1988). However, state resource management
agencies found the resolution of the 1 :7,500,000-scale map inadequate to meet their needs, which
led to a number of collaborative projects to refine and subdivide ecoregions at a larger (1 :250,000)
scale These projects have involved states, U.S. EPA regional offices, and the U.S. EPA -
National Health and Environmental Effects Research Laboratory, Western Ecology Division, m
Corvallis, Oregon. Completed projects cover Iowa, Massachusetts, Florida, and parts of Oregon,
Washington, Alabama, and Mississippi Projects still in progress for North Dakota, South
Dakota, Indiana, Ohio, and Tennessee have included participation by the U.S. Department of
Agriculture (USDA) - Natural Resources Conservation Service and the USDA - Forest Service as
part of an interagency effort to develop a common framework of ecological regions.
In this paper we have refmed level III ecoregions and delineated the more detailed level P /
subdivisions in a cooperative project with U.S. EPA Region 3, the Maryland Department of the
Environment, the Pennsylvania Department of Conservation and Natural Resources, the
Pennsylvania Department of Environmental Protection, the Virginia State Water Control Board,
and the West Virginia Department of Natural Resources. The impetus for this project was to
provide a spatial framework for developing biological criteria Hence, selection of regional
reference sites was a critical aspect and generally followed the approach outlined in Hughes
(1995) and Hughes and others (1986); it was carried out primarily under the direction of U.S.
EPA Region 3.
This project comprised two major stages. Initially, the subject area covered only the
parts of Maryland, Pennsylvania, West Virginia, and Virginia, located in the Blue Ridge
Mountains ecoregion (66), the Ridge and Valley ecoregion (67), and the Central Appalachians
ecoregion (69). After these ecoregions had been refined and subdivided (and then termed level Ill
or IV ecoregions) and stream reference sites had been selected, the Pennsylvania Department of
Environmental Protection negotiated with the U.S. EPA and its Environmental Monitoring and
Assessment Program (EMAP) to complete the ecoregionalization of the remainder of
Pennsylvania. As U.S. EPA Region 3’s interest in ecoregions evolved from creating a regional
biocriteria framework across state lines to serving the more comprehensive needs of the
developing Mid-Atlantic Highlands Project (MAHA), awareness of the need for ecoregions at the
state level also grew. Thus, the limits of the ecoregion mapping for this area are a combination of
state and ecoregion boundaries.
Evaluation of the ecoregion framework presented in this paper is a necessary future step.
U S. EPA ecoregions have been evaluated extensively in the past and the most meaningful of
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these efforts have involved the use of indices of water quality and biotic integrity (IBI) (Hughes,
1989a; Larsen and others, 1986, 1988; Whittier and others, 1987; Yoder and Rankin, 1995). A
better tool would be a more encompassing index of ecological integrity (TEl) (Omernik, 1995a,
1995b); although an JET is not available yet, there is considerable interest in at least two states to
begin its development. Verification of ecoregions cannot be done by considering individual
ecosystem components; this is because the ecoregion framework was not intended to show
regional patterns specific to either the flora or fauna of terrestrial ecosystems nor was it intended
to show patterns of fish or aquatic macro invertebrates.
METHODS
In brief, the procedure used to accomplish the regionalization process followed that of
snTular projects (Griffith and others, 1994a, l994b, 1994c) and consisted of compiling and
reviewing relevant materials, maps, and data; outlining regional characteristics; drafting level Ill
and IV ecoregion boundaries; digitizing boundary lines, creating digital coverages, and producing
cartographic products; and revising as needed after review by state managers and scientists. Tn
our regionalization process, we employed primarily qualitative methods. In other words, we
applied expert judgment throughout the selection, analysis, and classification of data to form the
regions. We based our judgment on the quantity and quality of component data and on
interpretation of the relationships between the data and other associated environmental factors.
This approach is similar to that commonly used in soils mapping (Hudson, 1992). More detailed
explanations of the methods, materials, rationale, and philosophy for this regionalization process
can be found in Omernik (1995a), Omernik and Gallant (1990), and Gallant and others (1989).
We based our ecoregion delineations on several criteria: (1) climate, (2) elevation, (3) land
use/land cover, (4) land form, (5) potential natural vegetation, (6) soil, (7) structurallbedrock
geology, and (8) surficiallQuaternary geology. General growing season and precipitation data
came from Cuff and others (1989) and Raitz and others (1984), and from county soil surveys of
the U.S. Department of Agriculture (USDA) - Natural Resources Conservation Service (NRCS)
(formerly Soil Conservation Service). Land use/land cover information was derived from the
general classification of Anderson (1970), from county soil surveys (USDA - NRCS), and from
1:250,000-scale topographic maps of the U.S. Geological Survey (USGS). Physiographic
information was gathered from Ciolkosz and others (1984), Cuff and others (1989), Fenneman
(1938), Geyer and Bolles (1979, 1987), Guilday (1985), and Hammond (1970). Information on
natural vegetation was obtained from many sources, including Cuff and others (1989), Kuchier
(1964), and county soils surveys (USDA - NRCS). Soil information came from regional
overviews (Ciolkosz and Dobos, 1989, Cunningham and Ciollcosz, 1984), from 1:250,000-scale
State Soil Geographic (STATSGO) maps derived from USDA - NRCS data, from state soil maps
(Higbee, 1967; USDA, 1972, 1979), and from county soil surveys (USDA - NIRCS). Geological
information came from Berg and others (1980), Cardwell and others (1968), Cleaves and others
(1968), county soil surveys (USDA - NRCS), Fullerton and Richmond (1981), and Milici and
others (1963). Topographic data were taken from 1:100,000 and 1:250,000-scale maps published
by the USGS. The 1:250,000-scale topographic maps were also used as base maps on which
level Ill and level IV ecoregion boundaries were plotted.
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REGIONAL DESCRIPTIONS
Pennsylvania and the Blue Ridge Mountains, the Ridge and Valley, and the Central
Appalachians of U.S. EPA Region 3 have been divided into 10 level ifi ecoregions and 37 level l v
ecoregions. Many of the boundanes of these ecoregions are transitional, and the ecoregion map
(Figure 1) should be interpreted with that in mind. Ecoregion descnptions follow and include
differentiatmg cnteria; their detail vanes and depends on available information. Appendix 1
contains ecoregion data summaries.
Northeastern Highlands (58);
Reading Prong (58h)
The Northeastern Highlands (58) extends from Canada through New England, New York,
and New Jersey to Wernersville Ridge m northeastern Pennsylvania. On the ecoregion map
(Figure 1), the Northeastern Highlands (58) contains one level IV ecoregion: the Reading Prong
(5 8h).
The Reading Prong (58h) is contiguous with the Taconic Mountains and the New England
Upland (Fenneman, 1938, p. 368) Its rounded summits typically range from 700 to 1,000 feet
(213-305 m) and are about 200-550 feet (61-168 m) above the intervening valleys. Maximum
elevation, about 1,400 feet (427 m), occurs on the Cambrian quartzite knobs of Wernersville
Ridge. Elsewhere, Precambrian granitic gneiss, Precambrian hornblende gneiss, and fanglomerate
are common (Berg and others, 1980). The metamorphic and igneous rocks are covered by slightly
acid, moderately fertile, residual soils which originally supported a native vegetation of
Appalachian oak forest, dominated by white oak (Quercus alba) and red oak (Quercus rubra)
(Cunningham and Ciolkosz, 1984; Cuff and others, 1989, p.52). Today, we see a mosaic of rural
residential development, woodland, and general farmland. Forest dominates oniy the more
rugged, stony, or elevated locations, and overall it is less dense than that of the Diabase and
Conglomerate Uplands (64b) or the higher Blue Ridge Mountains (66).
Figure 1 shows the boundaries of ecoregion 58h. Its dissected, rugged, crystalline hills are
higher and both physiographically different and hthologically distinct from ecoregions 64a, 64d,
and 67a.
Northern Appalachian Plateau and Uplands (60)
Ecoregion 60, in northeastern Pennsylvama, is a plateau made up of horizontally bedded,
nonresistant shales and siltstones and moderately resistant sandstones of Devonian age. It is
often lower and less forested than the adjacent Glaciated Allegheny High Plateau (62c) and crestal
elevations are typically 1,300-2,000 feet (396-610 m). Its rolling hills, open valleys, and low
mountains are partly covered by Olean till of Wisconsinan age and support a mosaic of cropland,
pastureland, and woodland. Soils are denved from till and are mostly mesic Inceptisols
(Cunningham and Ciol.kosz, 1984). Stoniness and seasonal wetness are common limitations of
these soils (Higbee, 1967). The natural vegetation was primarily Appalachian oak forest,
dominated by white oak (Quercus alba) and red oak (Quercus rubra). Some northern hardwood
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forest occurred away from the Susqueharina River at higher elevations; dominant trees included
sugar maple (Acer saccharum), yellow birch (Betula allegheniensis), beech (Fagus grand fo1ia),
and hemlock (Tsuga canadensis) (Cuff and others, 1989, p 52)
The boundaries of the Northern Appalachian Plateau and Uplands (60) are shown on
Figure 1 Its border with the North Central Appalachians (62), is based on topography, soils,
and land use; ecoregion 62 has greater forest density and is often more rugged and more elevated
than the more fertile Northern Appalachian Plateau and Uplands (60). Its border with the folded
and faulted, forested Ridge and Valley (67) follows the break in woodland density,
physiography, and geologic structure.
On the ecoregion map (Figure 1), the Northern Appalachian Plateau and Uplands (60) is
composed of two level IV ecoregions: the Glaciated Low Plateau (60a) and the Northeastern
Uplands (60b). Each is a mosaic of cropland, pastureland, and woodland on nearly horizontal
shales and sandstones. Descriptions of the individual charactenstics of these two ecoregions
follow.
Glaciated Low Plateau (60a)
The Glaciated Low Plateau (60a) is a mosaic of farmland, woodlots, and lakes upon low,
rolling hills. The terrain has been glacially smoothed, stream gradients are low, and the valleys are
open. Hilltop elevations are commonly 1,300-1,800 feet (395-550 m), and are often lower than
those of adjacent ecoregions. Local relief is typically 300-500 feet (9 1-153 m). The growing
season vanes inversely with elevation, increasing from 100 days in the northwest to 160 days m
the southeast. A corridor that is “favored from a climatic standpoint” (Murphy and Murphy,
1937, p. 371) bisects ecoregion 60a along the entrenched Susquehanna River at elevations of less
than about 820 feet (250 m).
The Catskill and Lock Haven (Chemung of New York) Formations of Devonian age
comprise the local bedrock (Berg and others, 1980). These rocks are less resistant than the
Mississippian and Pennsylvanian strata of the higher Glaciated Allegheny High Plateau (62c) and
are not deformed like those of the Sandstone Ridges (67c) Olean till of Wisconsinan age partly
covers the uplands and slopes and Quaternary glacial, lacustrine, and outwash deposits fill the
valleys.
Mesic and frigid Inceptisols (Fragiaquepts, Fragiochrepts, Dystrocbrepts) developed on
the dnft deposits (Cunningham and Ciolkosz, 1984). Leached and stony, they commonly have
fragipans and poor dramage.
The topography, climate, and soil make ecoregion 60a much more suitable for dairy
farming and livestock raising than for general crops. The crops that are grown tend to be directly
related to the daity-livestock regime and include hay, corn for silage, and oats. Idle farms are
increasing and woodland is common The native vegetation was mostly Appalachian oak forest,
with some northern hardwood forest occurring away from the Susquehanna River at higher
elevations (Cuff and others, 1989, p. 52). Bogs and marshes are common throughout ecoregion
60a.
The boundaries of the Glaciated Low Plateau (60a) are shown on Figure 1. Its eastern
boundary with the Northeastern Uplands (60b) follows the break in elevation, relief, channel
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gradient, valley-side slope angle, forest density, and stream density that are shown on the
Scranton 1:250,000-scale topographic map; all these are greater in ecoregion 60b than in ecoregion
60a. Its western border with the Glaciated Allegheny High Plateau (62c) is marked by a change
in forest density and elevation; both are greater in ecoregion 62c. Its southern border with the
Northern Sandstone Ridges (67c) occurs at the break in forest density, elevation, and geological
structure, there is less woodland density m ecoregion 60a than in ecoregion 67c which is folded
and faulted and higher in elevation.
Northeastern Uplands (60b)
The Northeastern Uplands (60b) shares many environmental characteristics with the
Glaciated Low Plateau (60a). However, these ecoregions can be distinguished by lake density,
slope angle, elevation, channel gradient, arid the ratio of woodland to farmland; all these are
greater m ecoregion 60b than in ecoregion 60a.
Ecoregion 60b is a dissected and glaciated plateau characterized by low, rollmg hills of
moderate relief and slope. More than half of the area is woodland, and lakes and bogs are very
common. Crestal elevations are commonly 1,400-2,000 feet (427-6 10 m), increasing to a
maximum of approximately 2,700 feet (823 m) at Mt. Ararat. Elevations are great enough to
insure a short growing season of 130-140 days. Near the bottoms of valleys, frost occurs late in
the spring and early in the autumn. Local relief typically ranges from roughly 650 feet (198 m)
down to about 130 feet (40 m), whereupon lakes and wetlands become particularly common.
Associated flora and fauna are found here. Bird life includes mallards (Anas plalyrhynchos),
Canada geese (Branta canadensis), wood ducks (Aix sponsa), and the American bittern (Botaurus
lentiginosus), which is threatened in Pennsylvania (Gill, 1985, p. 310).
The Inceptisols (Fragiaquepts, Fragiochrepts, Dystrochrepts) of ecoregion 60b are
denved from Wisconsinan drift and often suffer from poor drainage and stoniness (Cunningham
and Ciol.kosz, 1984; Higbee, 1967). The soil, climate, and terrain of ecoregion 60b support a
larger percentage of woodland and a smaller percentage of dairy and livestock farms than do those
of ecoregion 60a. Furthermore, farming is of declining importance; between 1982 and 1987, the
number of farms in ecoregion 60b decimed by about 13% and the number of acres in farms has
lessened by more than 10% (Pennsylvania Crop Reporting Service, 1983, p. 81, Pennsylvania
Agricultural Statistics Service, 1990-199 1, p. 82). Vacation cabins are increasingly common, but
they are not surrounded by extensive forest as they are in the Low Poconos (62b).
The soils have formed on Olean till and Quaternary glacial outwash. These m turn overlie
Devonian age sandstone, siltstone, and shale of the Catskill Formation (Berg and others, 1980).
The proportion of resistant sandstone is greater in ecoregion 60b than in ecoregion 60a, which
explains the difference m elevation between the two ecoregions. The strata of ecoregion 60b is
undeformed, unlike the rocks of the Northern Sandstone Ridges (67c); as a result, ecoregion 67c
also has more relief and forest density than ecoregion 60b.
The natural vegetation was mostly northern hardwood forest, exemplified by the
Woodbourne Forest and Wildlife Sanctuary near Montrose, Susquehanna County (Erdman and
Wiegman, 1974, p. 49). Some Appalachian oak forest occurs near the Susquehanna River (Cuff
and others, 1989, p. 52). Wetlands such as Madisonville and Mud Pond swamps are very
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common in areas of low relief, especially on the Moms-Wellsboro and Morris-Welisboro-Oquaga
soil associations.
Figure 1 shows the boundaries that divide the ecoregions. The western boundary between
the Glaciated Low Plateau (60a) and ecoregion 60b follows the break in elevation, relief, channel
gradient, valley-side slope angle, forest density, and stream density; all these are greater in
ecoregion 60b than in ecoregion 60a. The eastern boundary between ecoregion 60b and the more
dissected Low Catskills (62e) occurs at the forest density and topography break shown on the
Scranton 1.250,000-scale topographic map; ecoregion 62e is much more rugged and wooded than
ecoregion 60b. The southern boundary between ecoregions 60b and the Low Poconos (62b)
occurs at the forest density break shown on the Scranton 1:250,000-scale topographic map;
ecoregion 62b is more wooded than ecoregion 60b. In places, the border also follows the
hthological break between coarser and Imer members of the Catskill Formation and is near the
potential natural vegetation line dividing northern hardwood forest from Appalachian oak forest
(Cuff and others, 1989, p. 52)
Erie/Ontario Hills and Lake Plain (61)
Ecoregion 61, in northwestern Pennsylvania, is characterized by nearly level to rolling
terrain. Deposits from successive Pleistocene ice sheets and lakes cover the horizontally bedded
sedimentary rock. In places, beach ridges, hummocky stagnation moraines, kettles, and kames
can be found. Many wetlands still occur in the west and a high percentage of the threatened or
endangered species in Pennsylvania reside there. Local rehef ranges from less than 50 feet (15 m)
on the former lake plain to about 400 feet (122 m) on the till plain. Elevations range from about
570 feet (174 m) at Lake Ene to 2,000 feet (609 m) miand.
The most common soils are Alfisols and Inceptisols; they tend to be acid and are derived
mainly from till and lacustrine matenal. The lake plain and the wetter soils of the southwest
originally supported a beech/maple forest dominated by sugar maple (Acer saccharum) and beech
(Fagus grand fo1ia); elsewhere, northern hardwood forest occurred, with sugar maple (Acer
saccharum), yellow birch (Betula allegheniensis), beech (Fagus grandifolia), and hemlock (Tsuga
canadensis) as dominant trees (Cuff and others, 1989, p. 52).
The Erie/Ontario FUlls and Lake Plain (61) is the most important agricultural area in the
Allegheny Plateaus physiographic province (Cuff and others, 1989, p. 24). The lake plain
produces specialty crops, including fruits, vegetables, and nursery stock. The inland till plains,
with their much shorter growing season and wetter soils, are dominated by daity farming.
Associated erosion and stream pollution occur (Omernik and Gallant, 1988, p. 37).
The boundary of ecoregion 61 with the North Central Appalachians (62) and the Western
Allegheny Plateau (70) roughly corresponds to the Wisconsinan till himt. It also approximates
the natural vegetation transition between beech/maple and northern hardwood forests in the west
and Appalachian oak forest in the east (Cuff and others, 1989, p. 52).
On the ecoregion map (Figure 1), the Erie/Ontario Hills and Lake Plain (61) is composed
of three level IV ecoregions: the Erie Lake Plain (61a), the Mosquito Creek-Pymatuning
Lowlands (61b), and the Low Lime Drift Plain (61c). Each is dominated by agriculture and each
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has been glaciated in contrast to neighboring ecoregions Descriptions of the individual
characteristics of these three ecoregions follow
Erie Lake Plain (61a)
The narrow Ene Lake Plain (6 Ia) is characterized by nearly level terrain, lacustrine
deposits, a lake-modified climate, and distinctive crops Inland from the Lake Erie shoreline at
about 570 feet (174 m) elevation are gravelly beach ridges that mark the former shorelines of
glacial lakes Warren and Whittlesey Lacustrine deposits end at the highest late-Quaternary
shoreline, approximately 790 feet (241 m) Local relief is typically less than 50 feet (15 m), but
can be up to 100 feet (31 m) in the few northwesterly trending, steep-sided valleys This
entrenchment accompanied lake level reductions that occurred during the late-Pleistocene (Van
Diver, 1990, p 99)
Increased winter cloudiness and delayed coastal freezing are characteristics of ecoregion
61a Here, the growing season averages 194 days (Taylor, 1960) which is 3-10 weeks longer than
anywhere else in the adjacent Low Lime Drift Plain (61c) Lake Erie’s effect on climate is
especially pronounced within 5 to 6 miles (8-10 km) of the coast and disappears entirely 8 to 16
miles (13-26 km) from the shoreline (Taylor, 1960)
The agricultural crops grown on the Erie Lake Plain are distinctive to ecoregion 61a and
are adjusted to its favorable climate Grapes are the most valuable agricultural product
(Pennsylvania Agricultural Statistics Service, 1990-1991) Early matunng vegetables, including
asparagus, and fruit trees, including peach, apple, and cherry, are grown both on sandy soils and
on the gravelly soils of beach ridges Small fruits, including strawberries, and vegetables planted
late in the spring are grown on the low-lying silty and clayey soils of the swales (Taylor, 1960)
The natural vegetation was largely beech/maple forest, some chestnut (Ccistanea den/ala)
grew on gravelly soils (Flicks, 1934) Shoreline vegetation also occurred and is best preserved on
the sandy beaches, dunes, and flats of Presque Isle, which shelters Ene harbor Here grows
vegetation such as sea rocket (Ca/ale edentula), beach grass (Ammophilia brevthgulata), bluestem
(Andropogon gerardi), and Virginia pine (Pinus virginiana) (Cuff and others, 1989, p 56)
The Erie Lake Plain (61a) contains habitat that is rare or even unique in Pennsylvania
Presque Isle alone “has by far the largest concentration of periphery-of-range and disjunct
populations in Pennsylvania (R Latham, Department of Geology, University of Pennsylvania,
written communication, 1995),” thirty-five state rare species occur here (Cuff and others, 1989,
p 56) In addition, its lake shore bluffs that are composed of “landslide-prone drift and
lacustrine deposits have unusual flora (R Latham, Department of Geology, University of
Pennsylvania, written communication, 1995)” The threatened least bittern (Ixobrychus exilis
exths) and regal fntillary (Speyeria idalia) are found, respectively, in marshes and low wet
meadows (Gill, 1985, p 308, Opler, 1985, p 85)
The boundary between ecoregion 61a and the Low Lime Drift Plain (61c) follows the 790
foot contour, the highest late-Quatemary shoreline, to the north of this line, lacustrine deposits
begin, natural vegetation changes, and the climate moderates
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Mosquito Creek-Pymatuning Lowlands (61b)
The glaciated Mosquito Creek-Pymatuning Lowlands (61b) has nearly level to undulating
terrain It is characterized by poorly drained terrain caused by low relief, clayey substrate, and
fragipans The soils are mostly Alfisols (Fragiaqualfs, Fragiudalfs) and the substrate is primarily
clayey Hiram till of late-Wisconsinan age with some glacial outwash, alluvial, and lacustnne
deposits. Numerous wetlands and broad, flat-bottomed valleys occur on the silt and silty clayey
barns Low-gradient streams are common, have few nifies, and lack associated stream organisms.
Crestal elevations vary from about 900 to 1,300 feet (274-396 m) and local relief is usually less
than 150 feet (46 m).
The dairy industry is well suited to ecoregion 61b’s general soil, climate, and topography,
and there are many pastures. However, on well-dramed outwash soils, corn, potatoes, wheat,
and oats are sometimes grown; very poorly drained sites contain trees, idle land, brush, or
wetlands.
Natural vegetation was composed primarily of northern hardwood forest on the better
drained sites and beech/maple forest was found elsewhere. Remnants of the beech/maple forest
are preserved at Tyron’s Woods (southwest of Conneaut Lake) (Brenner, 1985, p. 14; Erdman
and Wiegman, 1974, P. 4). Marshes are common and contain many species, including cattails
(Typha spp.), bullrushes (Cladium jamaicensis), sedges (Carex spp.), and reed grasses
(Phragin:tes communis) (Brenner, 1985, p. 11). Shrub swamps and swamp forests cover large
areas of the Mosquito Creek-Pymatuning Lowlands (6 ib) and are more extensive than elsewhere
in Pennsylvania (R. Latham, Department of Geology, University of Pennsylvania, written
communication, 1995). The shrub swamps are composed of species such as buttonbush
(Cephalanthus occidentalis), swamp rose (Rosa palustris), poison sumac (Rhus vernix), and sillcy
dogwood (Cornus ammomum). Swamp forests contam species such as red maple (Acer
rubrum), white pine (Pinus strobus), and larch (Larix laricina). State Game Lands 214 near
Hartstown contains marshes, shrub swamps, and swamp forests and is the last remnant of the
Pymatuning Swamp, once about 16 square miles (42 km 2 ) in area (Erdman and Wiegman, 1974, p.
13).
The northern bald eagle (Hahaeetus leucocephalus alascanus) and the marsh-dwelling king
rail (Rallus elegans elegar s) (Gill, 1985, pp. 301-304), endangered in Pennsylvania, inhabit the
Mosquito Creek-Pymatuning Lowlands (61b). Several species threatened in Pennsylvania are
also found in the marshes and lakes of ecoregion 61b, including the least bittern (Ixobrychus exilis
exilis), the American bittern (Botaurus lentiginosus), and the black tern (Chlidonias niger
surinamensis) (Gill, 1985, pp. 307-3 14).
Figure 1 shows the boundary between ecoregion 61b and the Low Lime Drift Plain (61c).
Very poorly drained areas that are flat and often underlain by clayey Hiram till are included in the
Mosquito Creek-Pymaturnng Lowlands (61b); adjacent marshes and former marshes as shown on
7.5 minute quadrangles are also included in ecoregion 61b.
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Low Lime Drift Plain (61 c)
The glaciated Low Lime Drift Plain (61 c) is characterized by ground moraines, rolling
terrain, broad over-fit valleys, and numerous dairy farms. Terminal moraines, kettles, kames, and
poorly drained depressions are present locally. Glacial drift, primarily Kent till of late-
Wisconsinan age, overlies acidic, sedimentary rock of varying ages and types. Most soils have
fragipans and are poorly drained; they are typically rocky at the surface, low in carbonate, and
not especially fertile. The climate is continental and is not influenced by Lake Erie, except in
northernmost locations. The soil attributes and the short growing season make ecoregion 61c
poorly suited for cropland. Most of ecoregion 61c is best adapted to hay, oats, silage corn, and
pasture. Many ridges and lowlands are wooded or idle. Hilltop elevations range from about
1,100 feet to 2,000 feet (335-610 m) and local relief is typically 250-400 feet (76-122m).
The natural vegetation of the till plains was composed primarily of northern hardwood
forest on the better drained sites and beech/maple forest elsewhere. Near the Wisconsinan limit,
the Appalachian oak forest began and extended eastward into the Unglaciated Allegheny High
Plateau (62d) and the Pittsburgh Low Plateau (70c) (Cuff and others, 1989, p. 52). Marshes,
swamps, and bogs occur in areas of poor drainage (Geyer and Bolles, 1979, pp. 36-38). Muddy
Creek Research Natural Area in Crawford County contains virgin northern hardwood forest and
fine marshes (Erdman and Wiegman, 1974, p. 12). Columbus Bog-Tamarack Swamp in State
Game Lands 197 in Warren County, one of the best examples of a northern (kettlehole) bog in
western Pennsylvania, has a floatmg peat mat of sphagnum, sedges (Carex spp.), and sundew
(Drosera rotund folia), second growth tamarack (Larix laricina), and hemlock (Tsuga
canadensis) (Cuff and others, 1989, p. 55; Erdman and Wiegman, 1974, p. 9).
At least two plant species that are endangered in Pennsylvania inhabit ecoregion 61 c, the
Kaim’s lobelia (Lobelia kalmzz) and the endangered spreadmg globe flower (Trollius laxus). Both
are found in alkaline wet meadows (Wiegman, 1985, pp. 59, 71). Also inhabiting ecoregion 61c
are several species that are threatened in Pennsylvania, including the eastern sand darter
(Ammociypta pellucida) and the northern brook lamprey (Ichthyomyzonfossor) (Cooper, 1985,
pp 179, 182).
Figure 1 shows the boundaries of the Low Lime Drift Plain (61 c). To the east, ecoregion
61c extends to the approximate Wisconsinan ice limit, whereupon the potential natural vegetation
changes, dairy farming declines in importance, the terrain becomes more hilly, and the loamy
Kent till ends; in the Unglaciated Allegheny High Plateau (62d), forest land predominates and in
the Pittsburgh Low Plateau (70c) general farming is dominant. To the north, ecoregion 6lc abuts
the Erie Lake Plain (61a); here lacustrine deposits begin, natural vegetation changes, and the
climate moderates. To the northwest, ecoregion 61c continues until the landscape becomes flatter
and dominated by both wetlands and the clayey Hiram till of the Mosquito Creek-Pymatuning
Lowlands (61b).
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North Central Appalachians (62)
Ecoregion 62, in northcentral and northeastern Pennsylvania, is part of a vast, elevated
plateau composed of horizontally bedded sandstones, shales, siltstone, conglomerate, and coal It
is made up of plateau surfaces, high hills, and low mountains, and was only partly glaciated
Both the southwest and the glaciated east are low in comparison to the central section, which
rises to a general elevation of about 2,300 feet (701 m) on erosion resistant sandstones The
climate can be characterized as continental, with cool summers and cold winters Average annual
precipitation is from 33 to 50 inches (84-127 cm) and there can be as few as 100 days without
killing frost, the shortest penod in Pennsylvania Soils are often frigid and were derived from
sandstone, shale, and till, they are low in nutrients, and support extensive forests The original
vegetation was primarily northern hardwood forest, but scattered Appalachian oak forest and
isolated highland pockets of spruce/fir forest also occurred Land use activities are generally tied
to forestry and recreation but some coal and gas extraction occurs in the west
The boundary with the Ene/Ontario Hills and Lake Plain (61) is near the Wisconsinan till
limit, which approximates land use and natural vegetation breaks, ecoregion 62 is much more
forested than ecoregion 61 and it onginally lacked the beechlmaple component that once
dominated the Erie/Ontario Hills and Lake Plain (61) The border with the Western Allegheny
Plateau (70) and the Central Appalachians (69) approximates the land use and elevation breaks,
ecoregion 62 is more forested, cooler, and higher than the adjacent ecoregions The boundary
with the Ridge and Valley (67) occurs at the junction of folded and horizontal strata and also
approximates the border between the northern hardwood and the Appalachian oak forests. The
border with the Northern Appalachian Plateau and Uplands (60) occurs at the limit of resistant
strata, which causes elevation, climate, and forest density to change
On the ecoregion map (Figure 1), the North Central Appalachians (62) is composed of
five level l v ecoregions the Pocono High Plateau (62a), the Low Poconos (62b), the Glaciated
Allegheny High Plateau (62c), the Unglaciated Allegheny High Plateau (62d), and the Low
Catskills (62e) Each is forested and each is underlain by nearly horizontal rock, predominantly
sandstone Descnptions of the individual characteristics of these five ecoregions follow
Pocono High Plateau (62a)
The Pocono High Plateau (62a) is a forested highland of little relief It is studded with
lakes and wetlands and is underlain by undeformed, noncarbonate strata Elevations are great
enough to make ecoregion 62a higher and cooler than the nearby lowlands Glacial advances and
retreats have smoothed the terrain, disrupted drainage, produced hummocky morainal
topography, and carved many potholes Numerous resort and suburban developments occur,
especially around the glacial and artificial lakes Local relief is limited and commonly ranges from
50 to 175 feet (20-53 m) Stream gradients thus are also low and there are few riffles or riffle
inhabiting species
Wisconsinan till, glacial outwash, Recent alluvium, and, in the south, Illinoian till overlie
gently dipping Devonian and Mississippian strata The Duncannon and Poplar Gap-Packerton
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members of the Catskill Formation predominate and contain sandstone and conglomerate. These
rocks are more resistant to erosion than the finer material of ecoregion 62b. As a result, the
crestal elevations of ecoregion 62a, ranging from about 1,800 to 2,300 feet (549-701 m), are
markedly higher than those of ecoregion 62b, which range from about 1,300 to 1,500 feet (396-
457 m). An escarpment over 300 feef(91 m) high marks the juncture between ecoregions 62a and
62b and their respective hthologies. High-gradient streams and a few waterfalls, such as Indian
Ladder Falls, occur on the escarpment (Geyer and Bolles, 1979, p. 202).
The Pocono High Plateau (62a) is a famous year around resort region because of its
pleasantly cool summers, abundant snowfall, persistent winter snow cover, numerous lakes,
extensive woodland, public lands, tounst facilities, and proximity to urban centers In recent
years, ecoregion 62a has also experienced substantial suburban growth, resulting in stress to
environmental systems.
Soils derived from Wisconsinan drift are widespread and often very stony, acidic, low in
fertility, and poorly drained; these Inceptisols are almost always better suited to trees, wildlife,
and recreation than to other uses (Fisher and others, 1962, p. 2). The short growing season of
125-140 days reinforces this situation and, therefore, almost no commercially viable farming
occurs in ecoregion 62a. Limited areas are underlain by Illmoian till and have different soils than
occur further north on the younger tills; these soils are mostly Ultisols (Hapludults, Fragiudults)
and support the ecologically significant Pocono till barrens (R. Latham, Department of Geology,
University of Pennsylvania, written communication, 1995).
The natural vegetation of the Pocono High Plateau (62a) was predominantly northern
hardwood forest, with some Appalachian oak forest on the southern periphery. By 1870, almost
all the original forest had been cut over or burnt. Today, the mixed hardwood forest is mostly
second or third growth. Mature northern hardwood forest still can be found in Gouldsboro State
Park and virgin northern hardwood forestlspruce still occurs in Hickory Run State Park (Brenner,
1985, p 14, Erdman and Wiegman, 1974, p. 62). Wetlands are widespread and include marshes
and swamps such as those in Gouldsboro State Park and along Two Mile Run. Numerous
kettlehole bogs occur, includmg those at Pine Lake Natural Area and Bruce Lake; they are
composed of floating peat mats that grade into mixed hardwood swamps (Erdman and Wiegman,
1974, pp. 62-65; Van Diver, 1990, p. 97). “Mesic to hydric Pocono till barrens presently cover
some 6,000 acres near the southern rim of the Pocono Plateau, adjacent to xeric ridge top barrens
overlying sandstone covering an additional 6,000 acres. The glacial till barrens are a mosaic of
shrublands with scattered pitch pines variously dominated by scrub oak (Quercus ilicifolia),
sheep-laurel (Kalimia angvstifolia), and rhodora (Rhododendron canadense), a small proportion
of the barrens consists of pitch pine woodlands. The Pocono till barrens and adjacent swamps
comprise the largest concentration of globally rare communities and species in Pennsylvania; the
area is The Nature Conservancy’s highest priority for biodiversity conservation m the state (R.
Latham, Department of Geology, University of Pennsylvania, written communication, 1995).”
These barrens have a high diversity of moth and butterfly species (Cuff and others, 1989, p. 56).
The border between ecoregion 62a and the Low Poconos (62b) follows the break in
elevation, potential natural vegetation, and topography that occurs where coarser and finer
members of the Catskill Formation abut at the Pocono Plateau Escarpment. The division
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between the Ridge and Valley (67) and ecoregion 62a occurs where the high glaciated plateau
ends.
Low Poconos (62b)
The Low Poconos (62b) is a forested and glaciated plateau. Pleistocene ice sheets
smoothed its terrain, disrupted its drainage, and formed many shallow kettle lakes and wetlands.
In addition, it has many vacation and suburban developments, widespread public land, very little
agriculture, and extensive woodland. Local relief ranges from about 800 feet (244 m) down to 50
feet (15 m), where lakes and wetlands become particularly common. Areas of greatest rehef
occur adjacent to the Delaware River; here, high-gradient streams and waterfalls occur, including
Dingman’s Falls, which is the highest waterfall in Pennsylvania (Erdman and Wiegman, 1974, p
50; Geyer and Bolles, 1987, p. 253; Oplinger and Halma, 1988, p. 27).
Olean till, glacial outwash, glacial lake deposits, and Recent alluvium partly overlie gently
dipping Devonian age sandstone, siltstone, claystone, and shale. These rocks of the Long Run
and Walcksville Members of the Catskill Formation are much less resistant to erosion than those
of ecoregion 62a. As a result, ecoregion 62b is markedly lower in elevation than ecoregion 62a;
crestal elevations of ecoregion 62b are about 1,300 to 1,500 feet (396-457 m) whereas those of
ecoregion 62a are 1,800 to 2,300 feet (549-701 m)
Inceptisols are common m ecoregion 62b. They are derived from Wisconsinan dnft and
are often poorly drained, acidic, very stony, and low in fertility. As a result, these soils are
seldom suitable for agriculture and over 90% of the area is wooded.
Vacation and suburban developments occur throughout the region, especially near the
larger lakes. These developments have rapidly expanded in number to keep pace with population
growth, which has more than doubled in the last 25 years
The natural vegetation of the Low Poconos (62b) was mostly Appalachian oak forest.
Wetlands are very common and include marshes hke those of the Stillwater Natural Area and
swamps such as Saw Creek Headwaters Swamp, Nebo Swamp, Bald Hill Swamp, Tannersville
Cranberry Bog Preserve, and Walker Lake Swamp (Cuff and others, 1989, p. 54; Erdman and
Wiegman, 1974, pp. 49-61). Kettlehole bogs also occur, such as those at Lake Lacawac
Sanctuary and Little Mud Pond; they are composed of floating peat mats that grade into
hardwood swamp (Erdman and Wiegman, 1974, pp. 50, 55; Geyer and Bolles, 1979, p. 182).
The bog turtle (Cleinmys muhlenbergii) is found in the marshy meadows and sphagnum bogs of
Monroe County and is endangered in Pennsylvania (McCoy, 1985, p. 272). The king rail (Rallus
elegans elegans) is found in the marshes of Monroe County and is also endangered in
Pennsylvama (Gill, 1985, p. 303).
The boundary between ecoregion 62b and the Northeastern Uplands (60b) is found where
woodland density changes; it is much greater in ecoregion 62b. The border between ecoregions
62b and 62a follows the break in elevation, potential natural vegetation, and topography that
occurs where coarser and finer members of the Catskill Formation abut. The division between
the Ridge and Valley (67) and ecoregion 62b occurs where the glaciated plateau ends.
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Glaciated Allegheny High Plateau (62c)
Ecoregion 62c is a deeply dissected and forested highland composed of plateau remnants,
rounded hills, low mountains, and narrow valleys. Locally, especially in the south, the terrain
has been noticeably smoothed by glaciation. Here, many closed depressions and blocked valleys
occur and contain small lakes or shallow ponds. Nearly horizontal, resistant strata of
Mississippian to Devonian age underlie Wisconsinan drift and are responsible for the highland.
The Burgoon Sandstone is a prominent ridge former Hilltop elevations are commonly 1,900-
2,300 feet (579-70 1 m), which is high enough to ensure a short growing season of 100-165 days.
Local relief is about 300-700 feet (9 1-213 m) and reaches approximately 800 feet (244 m) in Pine
Creek Gorge. Mean annual precipitation ranges from 33 to 39 inches (84-99 cm). Most of the
soils are frigid Inceptisols, derived from acidic glacial drift, that are stony, acidic, low in fertility,
and often steep (Ciollcosz, 1989; Cunningham and Ciollcosz, 1983; Higbee, 1967).
The soils, climate, and ruggedness make the area well suited to trees and poorly suited to
agriculture. Hardwood forests are predominant. The natural vegetation was primarily northern
hardwood forest with some mtermixed bogs, swamps, and marshes. Appalachian oak forest also
occurred, especially on the eastern margin of ecoregion 62c (Cuff and others, 1989, p. 52).
Rickets Glen State Park in northwestern Luzeme County contains approximately 2,000 acres of
virgin northern hardwood forest, as well as numerous hemlock swamps (Erdman and Wiegrnan,
1974, p. 43). Pennsylvania’s only spruce bald occurs on Bartlett Mountain, western Wyoming
County (Roger Latham, Department of Geology, University of Pennsylvania, written
communication, 1995).
In terms of rock type, elevation, relief, natural vegetation, and prevailing land use,
ecoregion 62c is similar to the Unglaciated Allegheny High Plateau (62d). However, like the
Glaciated Low Plateau (60a), ecoregion 62c was covered with ice and has soils that were derived
from acidic glacial drift. Lakes and marshes and their associated flora and fauna occur in
ecoregions 62c and 60a, but not in 62d. The American bittern (Botaurus lentiginosus), which is
threatened in Pennsylvania, is found in the marshes of southern ecoregion 62c (Gill, 1985, p.
310).
Ecoregion 62c’s boundaries are shown on Figure 1. Its western border with the
Unglaciated Allegheny High Plateau (62d) occurs at the westward limit of Wisconsinan Olean till
(Berg and others, 1980) whereas its northwestern boundary occurs at an elevation break. The
eastern border with the Glaciated Low Plateau (60a) is based on forest density, elevation, and
rock type; ecoregion 60a has much less forest, is more than 300 feet (91 m) lower, is less rugged,
and has less resistant surficial rock than ecoregion 62c. The southern boundary is drawn along
Hucideberry Mountain and North Mountain, where terrain changes, folding begins, and elevation
changes by over 550 feet (168 m).
Unglaciated Allegheny High Plateau (62d)
Ecoregion 62d is a deeply dissected highland composed of plateau remnants, rounded
hills, low mountains, and narrow valleys. It is characterized by extensive forests, a short growing
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season, nutrient-poor residual soils, high local relief, nearly horizontal strata, resistant rock, and
oil wells Overall, the area is very rugged with steep valley sides, entrenched streams, high-
gradient channels, and many waterfalls Local relief is typically 550-700 feet (168-2 13 m) and
reaches about 1,300 feet (396 m) in valleys that were cut by large volumes of glacial melt water
The terrain is nowhere muted by glaciation, although its western-most parts were covered by at
least two pre-Wisconsinan glaciations Hilltop elevations increase northeastward across
ecoregion 62d They are commonly 1,700-2,200 feet (5 18-671 m) and are high enough to insure a
cool, humid climate with long winters The growing season lasts only 100-160 days, depending
on elevation and other microclimatic controls Mean annual precipitation ranges from 35 to 44
inches (89-112 cm) and increases westward Most of the soils are frigid Ultisols and Inceptisols
that are low in fertility, often steep, stony, and acidic, and were derived from noncarbonate
sedimentary rock
Extensive woodland occurs and national and state forests are common Oaks, maples, and
other hardwoods predominate, but hemlock (Tsuga canadensis), pitch pine (Pinus rigida), and
white pine (Pinus strobus) are also found
The natural vegetation was primarily northern hardwood forest with some intermixed
bogs and a perimeter of Appalachian oak forest (Cuff and others, 1989, p 52) Extensive logging
and burning removed most of the natural vegetation dunng the nineteenth century Remnants still
occur, however, including those at Tionesta Research Natural Area in southwestern McKean
County, Cook Forest State Park in eastern Clarion and southern Forest Counties, Hearts Content
Scenic Area in southern Warren County, Algerine Tamarack Swamp in northwestern Lycoming
County, and the Pine Creek Gorge Natural Area in western Tioga County (Cuff and others, 1989,
p 53, Erdman and Wiegman, 1974, as reported in Brenner, 1985, p 14, Geyer and Bolles, 1979,
p 67)
Oil wells are common throughout ecoregion 62d and account for more than 50% of
Pennsylvania’s total production There is also surface coal mining in the south and localized
valley agriculture in the northeast Pollution from mine drainage and oil production is a
significant problem locally and has degraded stream habitat (Biesecker and George, 1966, Plate 1,
Churchill, 1969, p 3, Dyer, 1982a, pp 117-118)
The western boundary between ecoregion 62d and the Low Lime Drift Plain (61c) is
associated with the breaks in topography, soil, and forest density that occur near the
Wisconsinan ice limit The eastern boundary between ecoregion 62d and the Glaciated Allegheny
High Plateau (62c) is at the limit of the Olean till of Wisconsinan age. The southeastern border is
drawn 3-6 miles (5-10 1cm) north of the West Branch of the Susquehanna River and Bald Eagle
Creek, where the terrain and elevation markedly change The southwestern boundary with the
Pittsburgh Low Plateau (70c) is drawn where elevation, forest density, and soil changes,
ecoregion 70c has lower elevations, less woodland density, and more Gilpin soils than ecoregion
62d The southern border divides the cooler, more heavily forested ecoregion 62d from the
Uplands and Valleys of Mixed Land Use (69b)
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Low Catskills (62e)
The Low Catskills (62e) is a forested and highly dissected ecoregion less than 5 miles (8
kin) wide in northeastern Pennsylvania. Here, the Delaware River has deeply entrench d into the
glaciated Appalachian Plateau, creating cliffs and steep-walled valleys. Many high-gradient
tributaries occur and stream organisms associated with riffles are common. Topography is rugged
for this part of the commonwealth and local relief ranges from about 450 to 800 feet (137-244 m).
Crestal elevations are from approximately 1,300 to 1,800 feet (396-549 m) and are high enough to
insure a short growing season of about 130 days, varying according to local topography and slope
aspect.
The soils of ecoregion 62e are mostly Inceptisols. Most formed on Olean till and some
developed on Quaternary alluvium They overlie nearly horizontal, Devonian age sandstone,
siltstone, and shale of the Catskill Formation. The soils are characterized by stoniness,
shallowness, [ ow fertility, and acidity, which, together with the rugged terrain and brief growing
season, make the area best suited to woodland (Higbee, 1967). The natural vegetation was
mostly northern hardwood forest (Cuff and others, 1989, p. 52) Some wetland vegetation
occurs on poorly drained sites, and northern rock plants grow on the Delaware River cliffs m
northeastern Wayne County (Erdman and Wiegman, 1974, p. 50).
The boundary between ecoregion 62e and the less dissected Northeastern Uplands (60b)
occurs at the forest density and topography break shown on the Scranton 1:250,000-scale
topographic map; ecoregion 62e is much more rugged and wooded than ecoregion 60b. Ecoregion
62e extends across the Delaware River into New York, where it becomes much more extensive.
Middle Atlantic Coastal Plain (63);
Delaware River Terraces and Uplands (63a)
The Middle Atlantic Coastal Plain (63) extends northeastward from Georgia to New
Jersey and includes an area of southeastern Pennsylvania adjacent to the Delaware River estuary.
On the ecoregion map (Figure 1), the Middle Atlantic Coastal Plain (63) contains one level l v
ecoregion: the Delaware River Terraces and Uplands (63a).
Ecoregion 63a is a narrow lowland characterized by an ocean modified climate, a long
growing season, tidally influenced rivers, freshwater intertidal marshes, and saltwater marshes. It
is dominated by Philadelphia and its suburbs, which developed on the Fall Line next to
Pennsylvania’s only estuary, the Delaware River. The nearly level to rolling terrain is underlain
by unconsolidated and easily eroded Quaternary gravels, sands, and silts. Elevations are less than
60 feet (18 m), local relief is less than 35 feet (11 m), and streams have low gradients and are
often tidally mfluenced.
Before settlement, Appalachian oak forest and loblolly pine forests grew on the Ultisols.
Today, these original forests are gone, but some mature, second growth occurs in the
Wissahickon Valley, Philadelphia (Erdman and Wiegman, 1974, p. 99),
Urban and industrial activities are now widespread and have caused extensive pollution
and habitat modification along the shore of the Delaware River. Erosion, development, dredging,
filling, and bulkheading have eradicated many wetlands and continue to have an impact on the few
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that still exist. The remaming freshwater mtertidal marshes of ecoregion 63a are home to globally
rare species; this habitat is severely endangered in Pennsylvania and the state’s only extinct
plant, Micranthemuin micranthenzozdes, was found there (R. Latham, Department of Geology,
University of Pennsylvania, written communication, 1995). Wetlands between Andalusia and
Bristol, including Neshammy State Park, are reported to contain several plant species endangered
in Pennsylvania, including the arrowhead (Sagzttaria calycina), coast violet (Viola brittoniana),
river bank quiliwort (Isoetes riparia), and swamp beggar-ticks (Bidens bidentoides) (Wiegman,
1985, pp. 44-48, 66-67, 74). The freshwater intertidal and saltwater Tinicum Marshes, near the
mouth of Darby Creek, contain several amphibian, reptile, and bird species that are endangered in
Pennsylvania, including the coastal plain leopard frog (Rana utricularia), red-bellied turtle
(Pseudemys rubriventris), bog turtle (Clemmys muhlenbergu), king rail (Rallus elegans elegans),
and short-eared owl (Asioflammeusfiammeus) (Gill, 1985, pp. 303-305; McCoy, 1985, pp 263-
271). These marshes are also the wintering ground for many ducks and provide summer habitat
for herons, egrets, gallinules, and bitterns, including the least bittern (Ixobrychus e.xzlis exilis) and
the Amencan bittern (Botaurus lentiginosus), which are threatened in Pennsylvania (Geyer and
Bolles, 1979, p. 469; Gill, 1985, pp 307-3 10).
The Delaware River itself has been severely affected by domestic and industrial pollution.
As a result, many associated species have been lost or are threatened with extinction in
Pennsylvania For example, the pirate perch (Aphredoderus sayanus), the mud sunfish
(Acantharchus pomotis), the blackbanded sunfish (Enneacanthus chaetodon), and the swamp
darter (Ertheostoma fusiforme) have been extirpated from the lower Delaware River of
Pennsylvania (Cooper, 1985, pp. 239-256). The shortnose sturgeon (Acipenser brevirostrum)
probably still exists in the Delaware River, but is endangered in Pennsylvania (Cooper, 1983, p.
5; 1985, pp. 171-172).
The Coastal Plain boundary approximates an elevation of 59 feet (18 m) (Geyer and
Bolles, 1979, p. 467; Guilday, 1985, p. 19) This border is near the Fall Line, which divides the
Lower Paleozoic schist and gneiss of ecoregion 64c from the much younger, less resistant, and
flat-lying sedimentary rocks. The boundary between the Piedmont Uplands (64c) and ecoregion
63a also approximates the juncture of the Chester and Glenelg soils with the Howell and
Fallsmgton soils (U.S. Department of Agriculture, 1972).
Northern Piedmont Ecoregion (64)
Ecoregion 64, in southeastern Pennsylvania, consists of low rounded hills, irregular plains,
and open valleys and is underlain by metamorphic, igneous, and sedimentary rocks. Crestal
elevations typically range from about 325 feet (99 m) on limestone to 1,050 feet (320 m) on more
resistant metamorphic rock. Isolated, higher, rocky hills and ridges occur and were formed by
diabase intrusions. The climate is humid continental, with cold winters, hot summers, and an
average of 170-200 days without killing frost. The natural vegetation was mostly Appalachian
oak forest. Some oak/hickory/pine forest occurred along the Susquehanna River and was
dominated by hickory (Carya spp.), Virginia pme (Pinus virginiana), pitch pine (Pinus rigida),
chestnut oak (Quercus prinus), white oak (Quercus alba), and black oak (Quercus velutina)
17
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(Cuff and others, 1989, p 52). There are scattered serpentine barrens in Chester, Delaware, and
Lancaster counties of Pennsylvania.
Soils within the Northern Piedmont (64) are generally deep, well-developed Alfisols and
Ultisols of moderate to excellent fertility. Those derived from the carbonate bedrock in the York
and Lancaster valleys are exceptionally fertile. Land use and land cover is a complex mix of small
farms interspersed with residential, commercial, and industrial development and scattered
woodland.
The boundary with the Middle Atlantic Coastal Plain (63) occurs at the Fall Lme The
border with the Ridge and Valley (67) is based on topography and geological structure
On the ecoregion map (Figure 1), the Northern Piedmont (64) is composed of four level
P1 ecoregions: the Tnassic Lowlands (64a), the Diabase and Conglomerate Uplands (64b), the
Piedmont Uplands (64c), and the Piedmont Limestone/Dolomite Lowlands (64d). Descriptions
of the individual characteristics of these four ecoregions follow.
Tnassic Lowlands (64a)
Ecoregion 64a is a plam underlam by sedimentary rock of Triassic age. Its low rolling
hills and broad valleys have a local relief of oniy 30-200 feet (9-6 1 m) and support a patchwork
of farms and houses. Typical hilltop elevations generally rise westward from 400 to 600 feet
(122-183 m). Ecoregion 64a is higher than the Piedmont Limestone/Dolomite Lowlands (64d),
but lower than either the Piedmont Uplands (64c) or the Diabase and Conglomerate Uplands
(64b).
The soils of ecoregion Ma were derived from sandstone, shale, siltstone, and argillite of
the Brunswick, Stockton, Lockatong, Gettysburg, and New Oxford Formations. The soils are
mostly Alfisols and have a moderate to high level of subsoil base saturation (Ciolkosz and
Dobos, 1989, p. 295; KuhI and others, 1984, p. 29). They are less fertile than the Alfisols of
ecoregion 64d, which were derived from carbonates, but are slightly more fertile than the Ultisols
and Inceptisols of ecoregion 64c, which were derived from metamorphic rock. Despite their soils
differences, ecoregions 64a and 64c have similar land uses.
A mosaic of farms and houses is typical of ecoregion 64a and has replaced the native
Appalachian oak forest. Agriculture is dominant southwest of the Susquehanna River and is
favored by nearness to market, fairly fertile soils, and a long growing season of 170-180 days.
Dairy farming is the main source of farm income; beef cattle, poultry, fruit, vegetables, and grain
are also important. Suburbanization increases toward Philadelphia.
Streams, wetlands, and a few ponds occur in ecoregion 64a. In the Schuylkill River
system of northern Montgomery and Chester counties, mallards (Anas platyrhynchos), Canada
geese (Branta canadensis), wood ducks (Aix sponsa), and black ducks (Anas ri bripes) are
common and the water is warm enough for many species of fish, including bass, bluegill, and carp
(Smith and others, 1967). Wetlands are becoming rarer, especially in the Philadelphia area, but
they still support populations of the New Jersey chorus frog (Pseudacris triseriata kahn:) and
the bog turtle (Clemmys muhlenbergii). both endangered in Pennsylvania (McCoy, 1985, pp.
261, 270).
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The boundanes of ecoregion 64a generally occur at the limit of nonresistant Triassic
deposits Changes in topography and soils often coincide with these boundaries
Diabase and Conglomerate Uplands (64b)
Ridges and hills composed of highly resistant igneous (diabase) or sedimentary rock
characterize ecoregion 64b They rise abruptly from the surrounding lowlands and are often
wooded, rocky, and steep Crestal elevations are typically 450-1,150 feet (137-35 1 m), but in
the Conewago Mountains, they nse to about 1,300 feet (396 m) Local relief varies substantially
from a minimum of about 50 feet to a maximum of 650 feet (15-198 m)
Ecoregion 64b is underlain mostly by Triassic conglomerates and reddish sandstones that
were intruded by Tnassic and Jurassic diabase along a series of linear sills and dikes These
intrusions in turn heated nearby sediments and altered them into harder, denser, and less porous
material (Geyer and Bolles, 1979, p 408) The primary ridge formers are the Gettysburg and
Hammer Creek conglomerates and, most commonly, diabase (trap rock) A famous example of
the latter is Gettysburg’s Cemetery Ridge
Mostly Alfisols developed on these rocks and onginally supported Appalachian oak
forest (Cuff and others, 1989, p 52) Today, woodland is still common in ecoregion 64b,
especially where the surface is steep or covered in rocks or boulders In other areas, the land is
more suitable to agriculture Here general farms occur, typically scattered among woodland and
idle land Camps and resort cottages are locally common, for example, in eastern Montgomery
County (Smith and others, 1967, p 9)
Lithology, woodland density, elevation, and topography differentiate ecoregion 64b from
the other ecoregions of the Northern Piedmont (64) Ecoregion 64b alone is a wooded upland
composed of resistant Jurassic and Triassic diabase and Triassic conglomerate
Piedmont Uplands (64c)
The Piedmont Uplands ecoregion (64c) is surrounded by the lowlands of ecoregions 63a,
64a, and 64d Ecoregion 64c is delineated by its underlying metamorphic rock and is
characterized by its rounded hills and low ridges Irregular plains and narrow valleys typically lie
from 130 feet to 330 feet (40 to 101 m) below the crests, whose elevations range from about 450
feet to 1,050 feet (137-320 m) Ruggedness increases toward the southwest and local relief can
be as much as 590 feet (180 m) adjacent to the incised Susquehanna River Here gorges
containing high-gradient streams and waterfalls occur, including Otter Creek, Tucquan Glen,
Wildcat Run, Counselman Run, Kelly Run, Ferncliff Run, and Oaldand Run (Geyer and Bolles,
1979, pp 442-465, Guilday, 1985, p 19)
Metamorphic rocks of Lower Paleozoic and Precambrian age underlie the ecoregion and
are folded and faulted Schists of the Wissahickon and Peters Creek Formations predominate and
Precambrian gneisses are common in the east Very resistant quartzite and phyllite of the
Chiclcies, Antietam, and Harpers Formations form the highest areas, the Pigeon Hills and Hellam
Hills Scattered outcrops of very basic serpentinite also occur
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Deep soils have been weathered from the schists and gneisses. Chester and Gleneig soils
are common. These Ultisols are capable of supporting highly diversified farms, even though they
are less fertile than the soils of ecoregion 64d. Soils derived from quartzite are commonly stony
and are often forested Chrome soils from serpentinite occur locally and are low in calcium and
high in magnesium, hromium, and mckel.
Appalachian oak forest originally was common in ecoregion 64c (Cuff and others, 1989,
p. 52), but mixed mesophytic forest also occurred. Remnants can be found in the cool, very
rugged Otter Creek gorge, where virgin chestnut oak (Quercus prinus), hemlock (Tsuga
canadensis), beech (Fagus grand folia), sugar maple (Acer saccharum), and basswood (Tilia
heterophylla) still grow (Erdman and Wiegman, 1974, p. 98).
Scattered serpentine barrens occur on chrome soils and support a specialized vegetation
composed of dry oaklpine forests (e.g, Quercus marilandica, Q stellata, Q velutina, Pin us
virginiana), greenbrier (Smilax rotundifolia), prairie grasses (e.g., Schizachyrium scoparius,
Sporobolus heterolepis), and herbs (e.g., Aster depauperatus, Cerastium arvense var.
villossissimum, Talinum teretzfolium) (Cuff and others, 1989, p. 56). Most of these are rare in
Pennsylvania and some are threatened, including the prairie dropseed (Sporobolus heterolepis)
(Wiegman, 1985, p. 57). In addition, the buckmoth (Ilemileuca mala) occurs only in the
serpentine barrens and is threatened in Pennsylvania (Opler, 1985, p 88). Pitch pine (Pinus
rigida) is a co-dominant in serpentine barren woodlands and an important component of
bluestem-dropseed savannas; it is found at seven serpentine barren sites in Chester, Delaware,
and Lancaster counties. Those at Nottingham County Park and at Goat Hill State Forest Natural
Area are among the largest remaining barrens in the eastern United States (Erdman and Wiegman,
1974, p. 99; R. Latham, Department of Geology, University of Pennsylvama, written
commumcation, 1995). Grazing, quarrying, and suburban development continue to threaten the
remaining barrens (Wiegman, 1985, p. 57) and The Nature Conservancy has given them second-
highest priority on their state biodiversity conservation agenda (Roger Latham, Department of
Geology, University of Pennsylvania, written communication, 1995).
Extensive urban, commercial, and industrial development occurs in the Philadelphia area.
Suburban development is common, especially near Philadelphia, Wilnimgton, and the major
transportation comdors. Conversely, farms become progressively more common with distance
from the cities. Grain, potatoes, and hay are produced and many of the farms have pastures for
dairy and beef cattle or ranges for poultry. Farming is favored by nearness to market, rather
fertile soils, and Pennsylvania’s longest growing season, up to 200 days. Agricultural erosion has
been a serious problem in many places (Kunkle, 1963)
The boundary of ecoregion 64c follows the limit of the Lower Paleozoic and Precambnan
metamorphic rocks; they are distinct from the largely sedimentary rock of the surrounding
ecoregions. The Northern Piedmont (64) is divided from the Middle Atlantic Coastal Plain (63)
by the Fall Line.
Piedmont Limestone/Dolomite Lowlands (64d)
Ecoregion 64d is a very fertile and intensively farmed area underlain mostly by limestone
and dolomite. These carbonates have been weathered to form a nearly level to undulating terrain
20
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that contains sinkholes, caverns, and disappeanng streams. Elevations are lower than adjacent
ecoregions, typically 325-525 feet (99-160 m). In the York Valley, however, they rise to about
675 feet (206 m) There is little dissection and local relief is typically only 30-125 feet (9-38 m).
Ordovician hmestone of the Conestoga Formation predominates. It is a high yieldmg
aquifer riddled with solution channels that reduce water filtration; as a result, groundwater is
sometimes contaminated. Other Ordovician and Cambrian Formations occur and contarn
limestone, dolomite, and shale.
The soils, unlike those of surrounding ecoregions, are derived largely from carbonate rock
and are very fertile. The Duffield and Hagerstown soils are common and, with the exception of
sinkholes, pose no limitations for agriculture. These Alfisols (Hapludalfs) developed under a
humid and mild climate.
Appalachian oak forest originally dominated ecoregion 64d, but along the Susquehanna
River, oak/hickory/pine forest also grew (Cuff and others, 1989, p. 52). Today, virtually all of
the forest has been replaced by agriculture A few wetlands still occur, mcludmg Gleisner’s
Swamp near Quarryville, the type locality of the bog turtle (Clemmys muhienbergu), which is
endangered in Pennsylvania.
The Piedmont Limestone/Dolomite Lowlands (64d) has a very favorable natural
environment for agriculture; its topography, climate/growing season, and market proximity are
conducive to commercial agriculture, and its soils are among the best in the United States (Cuff
and others, 1989, p. 20). It is one of the most productive agricultural areas in Pennsylvama and
is dominated by general farming Land use is similar in both the carbonate and the shale areas of
ecoregion 64d; corn, hay, soybeans, and wheat are commonly produced. Dairy farming also
occurs, but is not dominant as m neighboring ecoregions. In addition, tobacco is an economically
important specialty crop in Lancaster County, where it is typically grown on small, rotating
plots to reduce soil depletion (Pennsylvania Agricultural Statistics Service, 1990-1991).
Residential and industrial developments occur and are expandmg, especially in Montgomery
County and in the Lancaster area.
The boundary of ecoregion 64d generally follows the limit of Ordovician-Cambrian
carbonate rocks and the karst lowland. However, in the Conestoga Valley, shales of the Cocalico
Formation also occur.
Blue Ridge Mountains (66)
Ecoregion 66 is a narrow strip of mountainous ridges that are forested and well dissected.
Crestal elevations range from about 1,000 feet to over 5,700 feet (305-1,737 m) on Mt. Rogers
and tend to rise southward. Local relief is high and both the side slopes and the channel gradients
are steep Streams are cool and clear and have many riffle sections; they support a different, less
diverse fish assemblage than the streams of the valleys below, which are warmer, lower in
gradient, and more turbid.
The Blue Ridge Mountains (66) are underlain by resistant and deformed metavolcanic,
igneous, sedimentary, and metasedimentary rock. Inceptisols, Ultisols, and Alfisols have
developed on the Cambrian, Paleozoic, and Precambrian rock.
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The Blue Ridge Mountains (66) can be divided into northern (ecoregions 66a and 66b) and
southern parts (ecoregions 66c, 66d, 66e) at the Roanoke River (Hack, 1982). North of the river,
just three different rock types form the crest and the effects of differential erosion partially
determine their local altitude. South of the Roanoke River, the Blue Ridge Mountains become
higher and lithologically complex.
Climate vanes significantly. Generally, both growing season and precipitation mcrease
southward. The frost-free period varies from less than 150 days to more than 175 days, and the
precipitation varies from 39 to 49 inches (99-124 cm) Locally, however, relief and topographic
position have significant effects on the microclimate.
The natural vegetation varied from north to south. North of a transitional area near the
Roanoke River, it was predominantly Appalachian oak forest. South of the transitional area,
grew a mix of Appalachian oak forest, oak/hickory/pine forest, and, in higher areas, northern
hardwood forest (Kuchler, 1964). On the foothills, a mix of loblolly and shortleaf pines occurred
and were mixed with Appalachian oak forest.
On the ecoregion map (Figure 1), the Blue Ridge Mountams ecoregion (66) is composed
of five level IV ecoregions: the Northern Igneous Ridges (66a), the Northern Sedimentary and
Metasedimentary Ridges (66b), the Interior Plateau (66c), the Southern Igneous Ridges and
Mountains (66d), and the Southern Sedimentary Ridges (66e). Each is a highland that is
typically wooded and often composed of crystalline rock; each is distinct from the adjacent,
agncultural lowlands of the Northern Limestone/Dolomite Valleys (67a), the Southern
Limestone/Dolomite Valleys and Low Rolling Hills (670, the Southern Shale Valleys (67g), and
the Triassic Lowlands (64a).
Northern Igneous Ridges (66a)
Ecoregion 66a extends southwestward from South Mountam, Pennsylvania, to near the
Roanoke River. It consists of pronounced ridges separated by high gaps and coves. Mountain
flanks are steep and well dissected. Crestal elevations tend to rise southward, from 1,000 to
1,575 feet (305-480 m) in Pennsylvania, to a maximum of over 3,750 feet (1,143 m). Local relief
also increases southward to a maximum of about 1,300 feet (396 m).
Precambrian and Paleozoic metavolcanic and igneous rock underlie ecoregion 66a.
Typically occurring m Virginia are basalt and metabasalt of the Catoctin Formation, granite and
granodiorite of the Virginia Blue Ridge Complex, and andesite, tuft, and greenstone of the Swift
Run Formation. Metarhyolite and metabasalt occur in Pennsylvania; diabase, metabasalt, and
metarhyolite are found in Maryland. Inceptisols, Alfisols, and Ultisols have commonly
developed from the bedrock. Catoctin, Myersville, and Hayesville soils are widespread. Low
fertility, acidity, stoniness, and steepness are characteristics of these soils.
The natural vegetation was Appalachian oak forest (Kuchler, 1964). Today, the Northern
Igneous Ridges (66a) remain extensively forested. On South Mountain, however, localized dairy
farming and poultry raising occur; in addition, orchards are found on Arendtsville soils.
The boundary between ecoregion 66a and the Northern Sedimentary and
Metasedimentary Ridges (66b) is shown in Figure 1; it follows the contact between igneous-
metavolcanic rocks and sedimentary-metasedimentary rocks.
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Northern Sedimentary and Metasedimentary Ridges (66b)
Ecoregion 66b extends from South Mountain, Pennsylvania, to the Roanoke River area It
is composed of high, steeply slopmg ndges and deep, narrow valleys. Crestal elevations
typically nse southward, from about 1,300 to 2,000 feet (396-610 m) in Pennsylvania, to a
maximum of over 3,500 feet (1,067 m) Local relief also increases southward and reaches a
maximum of about 1,000 feet (305 m).
Erosion resistant sedimentary and metasedimentary rock of Cambrian age underlies
ecoregion 66b The Weverton-Loudon, Antietam (Erwin in Virgima), and Harpers (Hampton in
Virgmia) Formations are common. Typically, Inceptisols, Ultisols, and Alfisols developed from
the bedrock. Laidig, Wallen, Dekaib, Lily, Berks, and Weikert soils are widespread. Stoniness,
steepness, low fertility, and acidity are charactenstics of these soils Streams do not have much
buffering capacity and are subject to acidification.
The natural vegetation was Appalachian oak forest (Kuchler, 1964). Today, the Northern
Sedimentary and Metasedimentaiy Ridges (66b) remain extensively forested.
The boundary between ecoregion 66b and the Northern Igneous Ridges (66a) is shown in
Figure 1; it follows the contact between igneous-metavolcanic rocks and sedimentary-
metasedimentary rocks.
Interior Plateau (66c)
Ecoregion 66c is a high, hilly plateau punctuated by scattered isolated knobs
(monadnocks). The Interior Plateau (66c) is more than 1,000 feet (304 m) higher than the nearby
Piedmont; crestal elevations are approximately 2,600 to 4,500 feet (792-1,372 m). Local relief is
often under 200 feet (61 m).
Ecoregion 66c is underlain by Precambnan metamorphic rock, including quartzite,
graywacke, and conglomerate of the Lynchburg Formation. Gneiss and schist also outcrop.
Inceptisols, Alfisols, and Ultisols occur and Chester, Hayesville, Glenelg, Manor, and Myersville
soils are common. Stoniness and limited depth to bedrock are charactenstics of these soils.
The natural vegetation was Appalachian oak forest and oak/hickory/pine forest (Kuchier,
1964). Today, the Interior Plateau (66c) has woodlots interspersed with pastures. Dairy and
livestock farms are common and some apple orchards also occur. Woodland remams on steeper
slopes.
Ecoregion 66c’s boundary is shown in Figure 1; its muted relief, lower elevations, and
lower woodland density are a marked contrast to those of the Southern Igneous Ridges and
Mountains (66d) and Southern Sedimentary Ridges (66e) which are adjacent.
Southern Igneous Ridges and Mountains (66d)
Ecoregion 66d extends from near the Roanoke River into Tennessee and North Carolina
border. It consists of pronounced ridges and mountain masses separated by high gaps and coves.
Mountain flanks are steep and well dissected. Crestal elevations range from about 2,600 to 5,728
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feet (792-1,746 m) on Mt. Rogers. Local relief varies from about 1,150 to 1,500 feet (351-457
m).
Precambrian and Paleozoic rock underlies ecoregion 66d The Mt. Rogers Volcamc
Group, the Virginia Blue Ridge Complex, and the Lynchburg Formation are commonly exposed.
Typically, Inceptisols (Dystrochrepts) and Ultisols (Hapludults) developed from the bedrock.
The Hayesville and Grimsley, Porters soils are widespread and are characterized by stoniness
and steepness.
The natural vegetation was Appalachian oak forest or, at higher elevations, northern
hardwood forest (Kuchier, 1964). Today, the Southern Igneous Ridges and Mountains ecoregion
(66d) remains extensively forested.
The boundary between ecoregion 66d and the Southern Sedimentary Ridges (66e) is
shown in Figure 1, it follows the contact between igneous-metamorphic and sedimentary-
metasedimentary rocks
Southern Sedimentary Ridges (66e)
Ecoregion 66e extends from the Roanoke River into Tennessee. It is composed of high,
steeply sloping ridges and deep, narrow valleys. Crestal elevations range from about 2,600 to
4,425 feet (792-1,349 m) and are often higher than those of the Northern Sedimentary and
Metaseclimentary Ridges ecoregion (66b). Local relief ranges from about 500 to 1,150 feet (152-
351 m).
Cambnan sedimentary and metasedimentary rocks, including sandstone and quartzite of
the Chilowee Group, underlie ecoregion 66e. Ridge crests are underlain by resistant sandstone
and quartzite, while side slopes are made up of phyllite, shale, siltstone, and sandstone.
Typically, Inceptisols (Dystrochrepts) developed from the bedrock. The Berks, Weikert,
Dekalb, and Wallen soils are common.
The natural vegetation was Appalachian oak forest or, at higher elevations, northern
hardwood forest (Kuchier, 1964). Today, the Southern Sedimentary Ridges ecoregion (66e)
remains extensively forested.
The boundary between ecoregion 66e and the Southern Igneous Ridges and Mountains
(66d) is shown in Figure 1; it follows the contact between igneous-metamorphic and
sedimentary-metasedimentary rocks.
Ridge and Valley (67)
Ecoregion 67 extends from Wayne County, Pennsylvania, through Virginia along a
southwesterly axis. It is characterized by altematmg forested ridges and agricultural valleys that
are elongated and folded and faulted. Elevations range from about 500 to 4,300 feet (152-1,311
m). Local relief vanes widely from approximately 50 to 1,500 feet (15-457 m). The Ridge and
Valley (67) narrows toward the south and is generally bordered by the higher Blue Ridge
Mountains and the higher and less deformed Allegheny and Cumberland plateaus.
Underlying ecoregion 67 are largely Paleozoic sedimentary rocks that have been folded
and faulted. Sandstone, shale, limestone, and dolomite are the predominant rock types.
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Lithological characteristics often determine surface morphology. Many ndges are formed on
well-cemented, relatively resistant material such as sandstone or conglomerate; they are often
rather parallel and alternate with valleys but, m central Pennsylvania, they zigzag because
resistant strata were compressed into plunging folds during orogeny and later eroded Valleys
tend to be created on weaker strata, including limestone and shale. Inceptisols and Ultisols are
comnion and were developed on noncarbonate rock. Alfisols and Ultisols are found in the
limestone valleys.
The valleys vary in microtopography and agricultural potential Valleys derived from
limestone and dolomite are smoother in form and have a lower drainage density than those
developed in shale. Shale valleys often display a distinctive rolling topography. Soils derived
from limestone are fertile and well suited to agriculture, while those derived from shale have a
much lower agricultural potential unless they are calcareous.
Many of the streams networks are trellised; topography dictates that the swift, actively
down-cutting streams which run off steep ridges must jom the gentle valleys perpendicularly.
Other larger rivers such as the Susquehanna River cross structure, cuthng deep gorges through
ridges in the process. High-gradient streams are common in watergaps and on ridge slopes;
elsewhere, gentler gradient, warmer, more meandering streams are common. Partially as a result,
the latitudinally extensive Ridge and Valley (67) has good aquatic habitat diversity.
The natural vegetation varied from north to south From northeastern Pennsylvania to
near its border with Maryland, the Ridge and Valley (67) was dominated by Appalachian oak
forest. Southward, oak/hickory/pine forest was common to about the James River, whereupon
the Appalachian oak forest returned (Kuchler, 1964). Hemlock (Tsuga canadensis), along with a
mixture of white pine (Pinus strobus), beech (Fagus grand fo1ia), and other hardwoods also
occurred locally (Brenner, 1985, p. 13).
Climate varies significantly in the Ridge and Valley (67). Generally, both growing season
and precipitation increase southward. The frost-free period varies from less than 120 days to
more than 180 days and the precipitation varies from 36 to 50 inches (91-127 cm). Locally,
however, relief and topographic position have significant effects on the microclimate The Ridge
and Valley (67) is significantly lower than the Central Appalachians (69). As a result, it has less
severe winters, considerably warmer summer temperatures, and lower annual precipitation due to
a rain shadow effect.
On the ecoregion map (Figure 1), the Ridge and Valley (67) is composed of 10 level W
ecoregions: the Northern Limestone/Dolomite Valleys (67a), the Northern Shale Valleys (67b),
the Northern Sandstone Ridges (67c), the Northern Dissected Ridges (67d), the Anthracite (67e),
the Southern LimestoneiDolomite Valleys and Low Rollmg Hills (670, the Southern Shale
Valleys (67g), the Southern Sandstone Ridges (67h), and the Southern Dissected Ridges and
Knobs (67i). Each is underlain by folded and faulted sedimentary rock which is distinctive of the
ecoregion. The division between ecoregions 67a, 67b, 67c, and 67d and ecoregions 67f, 67g, 6Th,
and 67i occurs in a broad zone near the James River.
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Northern Limestone/Dolomite Valleys (67a)
Ecoregion 67a is a lowland characterized by broad, level to undulatmg, fertile valleys that
are extensively farmed. The Great Valley, the Shenandoah Valley, and the Nittany Valley aEl
occur in ecoregion 67a. Sinkholes, underground streams, and other karst features have developed
on the underlying limestone/dolomite, and as a result, the drainage density is low. Where streams
occur, they tend to have gentle gradients, plentiful year around flow, and distinctive fish
assemblages. Local relief typically ranges from 50 to 500 feet (15-1 52 m).
Silurian, Ordovician, and Cambnan limestone and dolomite commonly underlie ecoregion
67a. Interbedded with the carbonates are other rocks, mcluding shale, which give the ecoregion
topographic and soil diversity. Mesic Alfisols (Hapludalfs, Fragiudalfs, Paleudalfs) and Ultisols
(Hapludults, Paleudults) have developed from the rock. Hagerstown soils are common locally
and are very productive. They are also found on the Lancaster Plain and York Valley of the
Piedmont Limestone/Dolomite Lowlands (64d).
The climate of ecoregion 67a varies significantly because of the ecoregion’s elevational and
latitudmal range. The growing season varies from 145 to 180 days and is sufficient for
agriculture. Farming predominates, with scattered woodlands occumng in steeper areas. Kuchier
(1964) mapped the natural vegetation as mostly Appalachian oak forest in the north and
oak/hickory! pine forest in the south; bottomland forests also occurred.
Figure 1 shows the boundaries of Northern Limestone/Dolomite Valleys (67a); base-rich
soil, muted ten-am, low drainage density, and limestone, dolomite, and calcareous shale bedrock
are characteristic
Northern Shale Valleys (67b)
Ecoregion 67b extends over a large area from northeastern Pennsylvania to near the James
River in Virginia. Itis characterized by rolling valleys and low hills and is underlain mostly by
shale, siltstone, and fine-grained sandstone. Local relief varies from about 50 feet to 500 feet (15-
152m)
The Hamilton, Hampshire, Chemung, and Brallier Formations and, in Maryland, the
Chemung Group underlie ecoregion 67b. They are folded and faulted and are of Devonian age.
The underlying rocks are not as permeable as the limestone of ecoregion 67, so surface streams
are larger and drainage density is higher than in limestone areas. There is more soil erosion in
ecoregion 67b than in the Northern Limestone/Dolomite Valleys (67a) (Cuff and others, 1989, p.
21). As a result, the stream turbidity can be comparatively high and the stream habitat relatively
impaired.
Inceptisols (Dystrochrepts) have developed from residuum, and Berks, Weikert, and
Lehew soils are common. Soils derived from acid shale are poorer than the soils of ecoregion 67a,
which were derived from limestone (Cuff and others, 1989, p. 21). Within ecoregion 67b,
however, there is considerable soil variability, and some soils are more calcareous than others.
Kuchler (1964) mapped the natural vegetation as mostly Appalachian oak forest in the north and
oak/hickory/pine forest in the south; bottomland forests also occurred. Today, farming
predominates, with woodland occurring on steeper sites. Scattered shale ban-ens occur on steep
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west and south facing slopes; it is one of rarest types of habitat m Pennsylvania and occurs in
Huntingdon, Fulton, and Bedford counties (Cuff and others, 1989, p 56; Erdman and Wiegman,
1974, pp. 7 1-74)
The boundaries of ecoregion 67b are shown in Figure 1; they encompass acidic to neutral,
valley and low hill soils that developed on shales and siltstones
Northern Sandstone Ridges (67c)
Ecoregion 67c is characterized by high, steep, forested ridges with narrow crests. Crestal
elevations range from about 1,000 feet to 4,300 feet (305-1,311 m) and local relief typically
ranges from 500 to 1,500 feet (152-457 m) Most of the major ridges in ecoregion 67 are found m
ecoregion 67c or in the Southern Sandstone Ridges (67h). High-gradient streams flow off the
ridges mto narrow valleys. Streams do not have as much buffermg capacity as ecoregions 67d or
67i and are subject to acidification. The ridge-formmg strata are composed of folded, interbedded
Paleozoic sandstone and conglomerate. The Tuscarora Formation, Pocono Formation, Bald Eagle
Formation, and Clinton Group predominate. Other less resistant rocks, such as shale and
siltstone, may form the side slopes.
Inceptisols (Dystrochrepts) and Ultisols (Fragiudults) have commonly developed in the
residuum; they vary sigmficantly within a short distance as do rock type and elevation.
Typically, however, the soils are poor and sandy (Cuff and others, 1989, p. 21). Dekalb, Laidig,
Berks, Weikert, and Lehew soils are all common and slope angle, fertility, and stoniness are
limitations
Kuchier (1964) mapped the natural vegetation as mostly Appalachian oak forest in the
north and oak/hickory/pine forest in the south. Today, extensive forest covers this ecoregion.
Figure 1 shows the location of the sharp, wooded ridges and narrow, minor valleys of
ecoregion 67c Ridge contour lines are straight and parallel, not crenulated like those of the
Northern Dissected Ridges (67d).
Northern Dissected Ridges (67d)
Ecoregion 67d is composed of broken, dissected, almost hummocky ridges. It is underlain
by interbedded sedimentary rocks including siltstones.
Crestal elevations range from approximately 800 feet to 4,150 feet (244-1,265 m), and
local relief varies from about 200 feet to 1,150 feet (61-35 1 m). Streams tend to be less acidic
than those of ecoregion 67c and to have storm hydrographs with more peaks.
Ecoregion 67d is often underlain by the Brallier, Hampshire, Lock Haven, Chemung, and
Trimmers Rock Formations and, in Maryland, the Chemung Group. They are Devonian in age
and folded. The soils developed from this mterbedded rock are mostly Inceptisols
(Dystrochrepts). Dekalb, Berks, Weikert, and Lehew soils are common.
Kuchler (1964) mapped the natural vegetation as mostly Appalachian oak forest in the
north and oak/hickory/pine forest in the south. Today, forest covers most of this ecoregion, but
there are also some pastures. Shale barrens occur on steep west and south facmg slopes, they
consist of stunted trees [ including eastern red cedar (Juniper-us virginiana), Virginia pine (Pinus
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virginiana), and chestnut oak (Quercus prinus)], thickets of shrubs [ including hawthorn
(Crataegus unijiora), Allegheny plum (Prunus alleghaniensis), huckleberry (Gaylussacia
baccata)], and herbaceous vegetation [ including mountain parsley (Taenidia montana), moss pink
(Phlox subulata), barrens ragwort (Senecio antennarufolius), birdfoot violet (Viola pedata) and
Kate’s mountain clover (Trifolium virginicum) (Cuff and others, 1989, p. 56, Erdman and
Wiegman, 1974, pp 7 1-74) The shale barren habitat type is one of the rarest in Pennsylvania
and is found in Huntingdon, Fulton, and Bedford counties.
Figure 1 shows the location of the broken, dissected wooded ndges, knobs, and minor
valleys of ecoregion 67d. They are morphologically distinct from the sharp ndges and narrow
valleys of the Northern Sandstone Ridges (67c).
Anthracite (67e)
Ecoregion 67e in eastern Pennsylvania comprises an area that has been extensively
disturbed by anthracite coal mining and urban-industrial development. Landforms, soils, and
vegetation have all been indirectly or directly affected by mining operations and subsequent
runoff. Streams tend to be very acidic and to have high amounts of turbidity (Biesecker and
George, 1966, Plate 1; Kinney, 1964, p. 16; Dyer, 1982a; Herlihy and others, 1990, Table IV).
Associated habitat destruction has occurred. Crestal elevations range from about 1,000 to 1,650
feet (305-503 m) and local relief ranges up to 600 feet (183 m).
Pennsylvanian sandstone, shale, siltstone, conglomerate, and anthracite coal underlie
ecoregion 67e. The Llewellyn Formation and the Pottsville Group are exposed. The soils are
typically Entisols (Udorthents), Inceptisols (Dystrochrepts), and Ultisols (Fragiudults).
The natural forest was Appalachian oak forest with some northern hardwood forest.
Today cherry and birch are recolonizing some of the mined areas.
The boundaries of the Anthracite (67e) are shown in Figure 1 and enclose areas underlain
by anthracite-bearing strata, Udorthents, and low woodland density.
Southern Limestone/Dolomite Valleys and Low Rolling Hills (67f)
Ecoregion 67f is a lowland charactenzed by broad, undulating, fertile valleys that are
extensively farmed. Sinkholes, underground streams, and other karst features have developed on
the underlying limestone/dolomite, and as a result, the drainage density is low. Where streams
occur, they tend to have gentle gradients, plentiful year around flow, and distinctive fish
assemblages. Crestal elevations vary from 1,640 to 3,200 feet (500-975 m). Local relief
typically ranges from 150 to 500 feet (46-152 m).
Ordovician and Cambrian limestone and dolomite commonly underhe ecoregion 67f.
Interbedded with the carbonates are other rocks, including shale, which gives the ecoregion
topographic and soil diversity. Mesic Alfisols and Ultisols have developed from the rock.
The climate of ecoregion 67f is warmer than much of ecoregion 67a which lies to the north
and its growing season of 175 to 180 days is well suited for agriculture. Farming predominates,
with scattered woodland occurring in steeper areas.
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Figure 1 shows the boundaries of the Southern Limestone/Dolomite Valleys and Low
Rollmg Hills (670; base-rich soil, muted terrain, low drainage density, and limestone, dolomite,
and calcareous shale bedrock are characteristic. Kuchler (1964) mapped a natural vegetation
break near the boundary between ecoregions 67f and 67a, to the north in ecoregion 67a grew
oak/hickory/pine forest while to the south Appalachian oak forest was found.
Southern Shale Valleys (67g)
Ecoregion 67g extends from the James River into Tennessee It is characterized by rolling
valleys and low hills and is underlain mostly by fine grained rock. Local relief vanes from about
125 feet to 650 feet (38-198 m). The terram is often more rugged than that of ecoregion 67b.
Woodland occurs on steeper sites and farming is common elsewhere.
The Braiher, Rome, Elbrook, Chemung, and Clinton Formations commonly underlie
ecoregion 67g. They are folded and faulted, and are of Paleozoic age. The underlying rock is not
as permeable as the limestone of ecoregion 67, so surface streams are larger and drainage density
is higher than in limestone areas. There is more soil erosion m ecoregion 67g than in the Southern
Limestone! Dolomite Valleys and Low Rolling Hills (670; stream turbidity can, therefore, be
comparatively high and the nverine habitat relatively impaired.
Inceptisols and Ultisols have developed from residuum Soils derived from acid shale
commonly occur in ecoregion 67g and are poorer than the soils of ecoregion 67f, which were
derived from limestone. However, within ecoregion 67g there is considerable soil variability, and
some soils are more calcareous than others.
Figure 1 shows the boundaries of the Southern Shale Valleys (67g); they enclose acidic to
neutral valley and low hill soils that developed primarily on interbedded shales and siltstones.
To the north, in ecoregion 67b, grew oaklhickoiy/pine forest while, in ecoregion 67g, Appalachian
oak forest grew; bottomland forests also occurred
Southern Sandstone Ridges (67h)
Ecoregion 67h is composed of high, steep, forested ridges with narrow crests. Crestal
elevations range from about 2,300 feet to 3,450 feet (701-1,052 m), and local relief ranges from
approximately 500 to 1,500 feet (152-457 m). Most of the major ridges in ecoregion 67 are
found in ecoregions 67c and 6Th. The ridge-forming strata are composed of folded, interbedded
Paleozoic sandstone and conglomerate. Other less resistant rocks, such as shale and siltstone,
form the side slopes.
Inceptisols (Dystrochrepts) and Ultisols (Fragiudults) have commonly developed in the
residuum; they vary significantly within a short distance, as do rock type and elevation.
However, the soils are typically steep, stony, sandy, and low in fertility.
Kuchler (1964) mapped a natural vegetation break near the boundary between ecoregions
67h and 67c. To the north grew oak/hickory/pine forest and to the south, in ecoregion 6Th, grew
Appalachian oak forest. Today, extensive forest covers ecoregion 6Th
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Figure 1 shows the location of the sharp, wooded ridges and narrow, minor valleys of
ecoregion 67h Ridge contour lines are straight and parallel, not crenulated like those of the
Southern Dissected Ridges and Knobs (67i). Appalachian oak forests were charactenstic of the
ecoregion and were distinct from the oak/hickory/pine forest of the southern part of ecoregion
67c
Southern Dissected Ridges and Knobs (67i)
Ecoregion 67i is composed of broken, dissected, almost hummocky ridges. It is
morphologically distinct from the sharp ridges and narrow valleys of ecoregion 67h and underlain
by interbedded sedimentary rocks including siltstones. Crestal elevation ranges from
approximately 2,100 feet to 4,150 feet (640-1,265 m), and local relief varies from about 150 feet
to 800 feet (46-244 m). Streams tend to be less acidic than those of ecoregion 67h and to have
storm hydrographs with higher peaks.
Ecoregion 67i is often underlain by folded, mostly Devoman age sedimentary rocks; the
Chemung Group and the Brallier Formation are common. The soils developed from this
interbedded rock are mostly Inceptisols (Dystrochrepts) and Ultisols (Fragiudults); Berks,
Laidig, and Wallen soils are common.
Figure 1 shows the location of the broken, dissected wooded ridges, knobs, and minor
valleys of ecoregion 67i. They are morphologically distmct from the sharp ridges and narrow
valleys of the Southern Sandstone Ridges (67h). Appalachian oak forests were characteristic of
the ecoregion and distinguish it from the southern part of ecoregion 67d which was dominated by
oak/hickory/pine forests (Kuchler, 1964) Today, forest covers most of this ecoregion, but there
are also pastures.
Central Appalachians (69)
Ecoregion 69 includes parts of southcentral Pennsylvania, eastern West Virginia, western
Maryland, and southwestern Virginia. Itis a high, dissected, and rugged plateau made up of
sandstone, shale, conglomerate, and coal of Pennsylvanian and Mississippian age. The plateau is
locally punctuated by a limestone valley and a few anticlinal ridges. Its soils have developed
from residuum and are mostly frigid and mesic Ultisols and Inceptisols. Local relief varies from
less than 50 feet (15 m) in mountain glades to over 1,950 feet (594 m) in watergaps where high-
gradient streams are common. Crestal elevations generally increase towards the east and range
from about 1,200 feet to 4,600 feet (366-1,402 m). Elevations can be high enough to insure a
short growing season, a great amount of rainfall, and extensive forest cover. In lower, less rugged
areas, more dairy and livestock farms occur, but they are still interspersed with woodland. The
limestone of the Greenbrier River Valley supports permanent bluegrass pasture. Bituminous coal
mines are common and associated stream siltation and acidification have occurred (Biesecker and
George, 1966, Plate I; Herlihy and others, 1990, Table IV; Kinney, 1964, pp. 15, 16, 24).
The boundaries of ecoregion 69 are shown on Figure 1. Its eastern boundary with the
folded and faulted strata of the Ridge and Valley (67) occurs along the sandstone escarpment
known as the Allegheny Front or near the Greenbrier River or around the perimeter of Broad Top
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Mountain Its western boundary with ecoregion 70 occurs at the elevation and forest density
break, the more densely forested ecoregion 69 is higher, cooler, and steeper than the Western
Allegheny Plateau (70) and is underlain by more resistant rock Its northern border with the
North Central Appalachians (62) is based on climate, forest density and land use, ecoregion 69
has a less severe climate, less forest density, and a much lower oil well density than ecoregion 62
On the ecoregion map (Figure 1), the Central Appalachians (69) is composed of four level
IV ecoregions the Forested Hills and Mountains (69a), the Uplands and Valleys of Mixed Land
Use (69b), the Greenbner Karst (69c), and the Cumberland Mountains (69d) Descriptions of
the individual characteristics of these four ecoregions follow
Forested Hills and Mountains (69a)
Ecoregion 69a occupies the highest and most rugged parts of ecoregion 69 and is
extensively forested Its highly dissected hills, mountains, and ridges are steep sided and have
narrow valleys Crestal elevations are often 1,800 to 2,600 feet (549-793 m) and reach their
maximum, about 4,600 feet (1,402 m), in West Virginia Resistant sandstone and conglomerate of
the Pennsylvanian Pottsville Group, sandstone of the Mississippian Pocono Formation, and
sedimentary rocks of the Mississippian Mauch Chunk Formations are commonly exposed at the
surface and typically have a gentle dip In some places, however, the strata have been gently
folded into a series of northeasterly trending ridges that reach an elevation of 3,200 feet (975 m)
These anticlinal ridges, Chestnut Ridge, Laurel Mountain, and Negro Mountain, form a transition
between the relatively undeformed Western Allegheny Plateau (70) and the folded and faulted
Ridge and Valley (67) (Ciolkosz and others, 1984, p 9) Broad Top Mountain, Pennsylvania is
an outlier of the Forested Hills and Mountains (69a) that is surrounded by ecoregion 67, its
lithology and surface topography resemble ecoregion 69a despite its geographical position
(Guilday, 1985, p 23) Local relief varies widely, on mountain bogs (glades), topography can be
almost flat, whereas adjacent to watergaps, such as the Conemaugh River Gorge, local relief can
exceed 1,300 feet (396 m) The eastern woodrat (Neotomafiorzdczna), found on the cliff faces and
boulder piles of water gaps, has been classified as threatened in Pennsylvania (Genoways, 1985,
p 362) Cool water, steep-gradient streams and waterfalls occur and have a less diverse fish
population than those nearer the Ohio River Characteristically, the streams of ecoregion 69a do
not have much buffenng capacity and many reaches, including some not affected by mme
drainage, are too acidic to support fish (R Webb, Department of Environmental Sciences,
University of Virginia, written communication, 1995)
Mean annual precipitation varies from about 38 to 60 inches (96-152 cm), while the
average growing season is only 13 5-155 days (U S Department of Agriculture, 1972) The high,
rugged topography has a heavy impact on the climate The average annual temperatures of
ecoregion 69a can be more than 10°F (5°C) lower and the average rainfall can be from 20% to
100% higher than in the adjacent Ridge and Valley (67) (Williams and Fridley, 1938) Higher
elevations get more precipitation and have a shorter growing season than lower elevations
Prevailing westerly winds bring substantial precipitation to the windward side of the mountains
Most of the soils are frigid and mesic Ultisols (Hapludults, Fragiudults) and Inceptisols
(Dy strochrepts, Fragiochrepts, Haplaquepts) that are acidic, steep, often stony, and low in
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nutnents. The relatively infertile soils, cool climate, short growing season, and ruggedness of
ecoregion 69a make the area particularly unsuited to agriculture The onginal vegetation was
mostly Appalachian oak forest, northern hardwood forest, and mixed mesophytic forest.
Scattered areas of northeastern spruce/fir forest occurred at especially high elevations (Cuff and
others, 1989, p. 52; Kuchler, 1964). Today, extensive forests of hard maple, black cherry, birch,
and red oak dominate many areas Conifer belts can be found in the high and cool localities and
are dominated by red spruce (Picea rub ens) and hemlock (Tsuga canadensis) (Williams and
Fndley, 1938). The white monkshood (Aconitum reclinatum) is found in moist mountain woods
and adjacent floodplains of Somerset County, Pennsylvania, and is endangered in the state
(Wiegman, 1985, p 57). Glades, including Cranbeny Glades northwest of Hillsboro, occur in
highland bowls that trap cold air and have restricted water drainage; sphagnum moss, black
spruce (Picea mariana), and tamarack (LarLx laricina) grow here (Raitz and others, 1984, p 70).
Gas wells and bituminous coal mines are locally common, and associated stream and land
degradation occurs Agriculture is usually restricted to livestock or dairy farming, but many
fields are reverting to woodland or have been planted with Chnstmas trees.
The boundary between ecoregion 69a and the Pittsburgh Low Plateau (70c) is determined
primarily by land use, geology, and elevation and is shown on Figure 1; the more densely forested
ecoregion 69a is higher and steeper than ecoregion 70c and is underlam by different, more
resistant rock strata. Land use and rock type differentiate ecoregion 69a from the Uplands and
Valleys of Mixed Land Use (69b); the more densely forested ecoregion 69a is underlain by
sandstone and conglomerate of the Pennsylvanian Pottsville Group, sandstone of the
Mississippian Pocono Formation, and sedimentary rocks of the Mississippian Mauch Chunk
Formations whereas ecoregion 69b is composed of shale, siltstone, and sandstone of the
Conemaugh Group Land form and rock type separates ecoregion 69a from the folded and
faulted Ridge and Valley (67); often, the boundary follows the high sandstone escarpment of the
Allegheny Front.
Uplands and Valleys of Mixed Land Use (69b)
Ecoregion 69b is a dissected upland plateau characterized by a mosaic of woodland and
agriculture; it includes a small outlier on Broad Top Mountain, Pennsylvama. Bituminous coal
mines are numerous. The rounded hills and low ridges attain elevations of 1,375-2,800 feet (4 19-
853 m), high enough to produce a rather short growing season of 135-165 days. Local relief
ranges from less than 50 feet (15 m) in glades to about 1,000 feet (305 m).
Pennsylvania shales, siltstones, sandstones, and coals of the Allegheny Group, and
especially the Conemaugh Group, are extensively exposed and nearly horizontal. Soils of low to
moderate fertility have weathered from this rock and are mostly mesic Ultisols (Hapludults,
Fragiudults) and Inceptisols (Dystrochrepts).
The natural vegetation was primarily Appalachian oak forest and mixed mesophytic
forest (Cuff and others, 1989, p 52; Kuchler, 1964). Scattered glades composed of sphagnum
moss, black spruce (Picea mariana), and tamarack (Larzx laricina) also occurred. Isolated
remnants of the original vegetation can still be found and Markelysburg Bog, near Farmington,
Pennsylvania, is the type locality of the Allegheny glade gentian (Gentian saponaris var.
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Allegheniensis) (Erdman and Wiegman , 1974, pp. 25, 32). Today, about 60-70% of ecoregion
69b is forested, in Christmas tree plantations or reverting to woodland. Dairy farmmg and
livestock raising are the main agricultural pursuits.
Bituminous coal mines are common, and in some areas, such as Clearfield County,
Pennsylvania, they affect more than 10% of the land surface (Hallowich, 1988). Associated
stream siltation and acidification have occurred (Biesecker and George, 1966, Plate 1; Dyer,
1982b, Herlihy and others 1990, Table IV)
The boundary between ecoregions 69b and 70c is detenmned pnmanly by land use,
geology, and elevation and is shown in Figure 1; the more densely forested ecoregion 69b is
higher, cooler, and steeper than ecoregion 70c and is underlain by more resistant rock. Land use,
elevation, and rock type differentiate ecoregions 69b from 69a; ecoregion 69b, largely underlain
by the Conemaugh Group, is lower and often less forested than ecoregion 69a, which is underlain
largely by the sandstone and conglomerate of the Pennsylvanian Pottsville Group, sandstone of
the Mississippian Pocono Formation, and sedimentary rock of the Mississippian Mauch Chunk
Formations The border between ecoregions 62d and 69b is based on forest density and land use;
ecoregion 69b has a lower forest density and a much lower oil well density than ecoregion 62d.
Greenbrier Karst (69c)
Ecoregion 69c is a rolling, agricultural lowland punctuated by isolated hills. Karst
landscape is common, such as at Little Levels, and developed on limestone Saucer-shaped
sinkholes and underground solution channels occur; stream density therefore is low. Resultant
subsurface dramage feeds the Greenbner River, which has large amounts of year around, high-
quality flow. Crestal elevations range from about 1,800 to 2,900 feet (549-8 84 m). Lower areas
have an adequate growing season (up to 165 days) for pasture, small grain, and corn (Gorman,
1972). Valley bottoms are typically 150 to 650 feet (46-198 m) below hilltops. Where river
incision occurs, however, local relief sometimes reaches 1,000 feet (305 m).
Ecoregion 69c is underlain mostly by limestones of the Greenbrier Formation. Other
Mississippian strata also occur, however, including the Bluefleld and Maccrady Formations, and
are composed pnmarily of limestone and shale. Deep, gently sloping and well-dramed soils,
which are moderately fertile to fertile, developed on the sedimentary rock. The soils are mostly
Ultisols (Hapludults, Paleudults), Alfisols (Hapludalfs), and Inceptisols (Dystrochrepts).
Frederick, Frankstown, Westmoreland, Litz, Gilpin, Calvin (often high-base substratum) soils are
locally common.
Oak/hickory forest was originally common in Greenbrier Karst (69c) whereas mixed
mesophytic forest occurred m adjacent ecoregions (Raitz and others, 19S4, p. 70). By 1938,
only scattered woodland remained. Stands dominated by white oak (Quercus alba), red oak
(Quercus rubra), and sugar maple (Acer saccharum) occurred only on the limestone soils of
steeper slopes (Williams and Fridley, 1938). Elsewhere, such as on the Big Levels and the Little
Levels, bluegrass pasture and hay crops predominate. These permanent pastures have remained
excellent smce they were cleared in the late-l8th century and support beef cattle, sheep, poultry,
and dairy farming. The Greenbrier Karst (69c) is among West Virginia’s principal livestock
producing areas (Raitz and others, 1984, p. 70)
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The ecoregion boundary follows the break in topography, geology, land use, natural
vegetation, and soil; karst topography, limestone bedrock, permanent pastures, onginal
oak/hickory forest, and fertile, high base soils are charactenstic of ecoregion 69c and are absent
from adjacent ecoregions (Figure 1).
Cumberland Mountains (69d)
The Cumberland Mountains (69d) is a strongly dissected region with steep slopes, very
narrow ridgetops, and extensive forests. It is pnmanly underlain by flat-lying Pennsylvanian
sandstone, siltstone, shale, and coal of the Pottsvile Group. Typically, crests range in elevation
from 1,200 feet to about 3,600 feet (366-1,097 m) and are from 350 to 550 feet (107-168 m)
above the narrow valleys. Well-drained soils of low to moderate fertility have developed on the
sedimentary rocks. Clymer, Dekalb, and Jefferson soils are common and are Ultisols
(Hapludults) and Inceptisols (Dystrochrepts) (Cunningham and Ciotkosz, 1984; U S
Department of Agriculture, 1979). They originally supported mostly mixed mesophytic forest
(Kuchler, 1964). Today, commercial woodland is common in ecoregion 69d and approximately
90% of the rugged ecoregion is forested or reverting to it (U.S. Department of Agriculture, 1979).
Much of the remainder is mined for coal, and stream degradation has occurred (Dyer, l982b;
Herlihy and others, 1990, Table IV; Kmney, 1964, p. 24). In wider valleys, scattered towns and
small-scale livestock farms are found.
The boundary between ecoregion 69d and the Forested Hills and Mountains (69a) divides
different fish assemblages and approximates the border between Land Resource Associations 125
and 127 (U S. Department of Agriculture, 1979); it generally follows a topographic and
elevational break with ecoregion 69d more highly dissected and slightly lower than ecoregion 69a.
The boundary between ecoregion 69d and the Ridge and Valley (67) approximates a major
structural topographical, lithological, elevational, and land use break.
Western Allegheny Plateau (70)
Ecoregion 70, in southwestern Pennsylvania, is a low, dissected, and mostly unglaciated
plateau. Rounded hills, narrow valleys, and alluvial terraces characterize the terrain north of
Pittsburgh. To the southwest of Pittsburgh, the terrain gradually becomes more rugged and
finally closes into ridges near the West Virginia border. Crestal elevations are less than 2,000 feet
(610 m) and local relief is approximately 200 to 550 feet (61-168 m).
The Western Allegheny Plateau (70) is composed of horizontally bedded sandstone,
shale, siltstone, limestone, and coal of Pennsylvanian and Permian age. The soils weathered from
these rocks are commonly Alfisols. The natural vegetation was primarily Appalachian oak forest
with some mixed mesophytic forest occurring, especially in the south (Cuff and others, 1989, p.
52).
The land use and land cover is a mosaic of urban-suburban-industrial activity, general
farms, pastures, forests, coal mines, and oil-gas fields. Urban and industrial land use
predominates along the major rivers, especially m the Pittsburgh area. Elsewhere, agricultural
land is common except in rugged areas where forests are dominant. Bituminous coal mining is
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widespread and has affected large tracts of land, especially in Armstrong and Clarion counties,
where 2-3.9% of the surface area has been stripped away (Cuff and others, 1989, P. 41). Mining
and mdustnal operations dimmished water quality and reduced fish diversity in the Allegheny,
Monongahela, Youghiogheny, and Ohio river systems; recent stream quality improvements have
occurred (Cooper, 1985, p. 170).
The boundary with the Erie/Ontano Hills and Lake Plain (61) approximates the
Wisconsman till limit The boundary with the North Central Appalachians (62) approximates
land use/land cover and elevation breaks; ecoregion 62 is more forested, cooler, and higher than
ecoregion 70. The border with the Central Appalachians (69) approximates the break in elevation
and forest density that occurs near the limit of the Pennsylvaman Allegheny Group (Figure 1);
the more densely forested ecoregion 69 is higher, cooler, and steeper than the Western Allegheny
Plateau (70) and is underlain by more resistant rock
On the ecoregion map (Figure 1), the Western Allegheny Plateau (70) is composed of
three Level IV ecoregions: the Permian Hills (70a), the Monongahela Transition Zone (70b), and
the Pittsburgh Low Plateau (70c). Each is unglaciated, underlain by horizontal sedimentary rock,
and mined for coal. Descriptions of the individual charactenstics of these three ecoregions
follow.
Permian Hills (70a)
The Perrman Hills (70a) is isolated from the population and industry of the Ohio and
Monongahela valleys by distance and topography. Few flat areas occur in ecoregion 70a. The
terrain becomes more rugged toward the southwest, as the rounded hills and shallow valleys
gradually close into ridges Crestal elevations also increase toward the southwest and range from
about 1,175 to 1,600 feet (358-488 m). Local relief is 400-550 feet (122-168 m) and is more than
that of the Monongahela Transition Zone (70b).
Dormont, Culleoka, and Newark soils are common and were denved from Permian shale,
limestone, sandstone, and coal of the flat-lying Greene and Washington Formations. These soils
are mostly Alfisols and are similar to those of ecoregion 70b. They are distinct from the soils of
ecoregion 70c and supported a natural vegetation of Appalachian oak forest and, to a lesser
extent, mixed mesophytic forest (Cuff and others, 1989, p. 52).
Most of the acreage is too steep to be farmed and is in woodland or reverting to it,
elsewhere, there is corn and hay farming on the ridges and pastureland on the hillslopes
Significant slope erosion has been caused by inappropriate grazing and cultivation practices, and
top soil is often thin or absent on uplands (Guilday, 1985, p. 24). Bituminous coal mining and
oil and gas production occur in ecoregion 70a.
Inhabiting ecoregion 70a is at least one species that is endangered, the small-whorled
pogonia (Jsotria medeoloides). This woodland orchid was the first Pennsylvania species listed
by the federal government as endangered (Wiegman, 1985, p. 49).
The boundary between ecoregions 70a and the Monongahela Transition Zone (70b)
generally follows the geologic division between the Washington and Waynesboro Formations.
The Permian Hills (70a) ecoregion is more rugged, more forested, and cooler than ecoregion 70b.
The border is visible on the Seasonal Land Cover Regions map produced from advanced very high
35
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resolution radiometry (AVHRR) from satellite (Loveland and others, 1995; U S. Geological
Survey, 1993).
Monongahela Transition Zone (70b)
The Monongahela Transition Zone (70b) is characterized by urban, suburban, industrial,
and mining land uses superimposed on a sparsely wooded, unglaciated terrain of rounded hills
and open valleys. Entrenched rivers, gently dipping strata, and land slips occur. The landscape
is less dissected, less closed, and more rounded than the neighboring Pittsburgh Low Plateau
(70c) Summits are often 1,200-1,300 feet (366-396 m) in elevation. Local relief is 200-350 feet
(61-107 m) and is less than that in either ecoregion 70c or the Permian Hills (70a).
Guernsey, Dormont, Culleoka, and Westmoreland soils are common and have developed
on the interbedded limestone, shale, sandstone, and coal of the Monongahela Group and the
Waynesboro Formation. These Alfisols typically have a higher base saturation than the soils of
ecoregion 70c and once supported a natural vegetation of mostly Appalachian oak forest (Cuff
and others, 1989, p. 52)
Urban, suburban, and industrial activity predominates. Much of it is crowded into the
narrow nver valleys that also serve as transportation corridors. Bituminous coal mining is
common and some oil production occurs. There is also some general farming and woodland, but
these are less prevalent than in ecoregion 70c.
Acid mine dramage, siltation, and industrial pollution have degraded stream habitat in
ecoregion 70b affecting fish and invertebrates. As a result, the eastern sand darter (Ammociypta
pellucida) was extirpated from the Ohio River drainage of Pennsylvania (Cooper, 1983, p. 189)
and the obscure clubtail dragonfly (Pro gomphus obscurus) disappeared from the Allegheny River
system (Opler, 1985, p. 138). Subsequent improvement of water quality has occurred and some
species have reappeared upstream from Pittsburgh, mcludmg the smalimouth buffalo (Ictiobus
bubalus) (Cooper, 1985, pp. 177-183).
The boundary between ecoregions 70b and 70c generally follows the geologic division
between the limestone-bearing Monongahela Group and the noncarbonate Conemaugh Group.
This line conforms to where the soils of ecoregion 70c meet the base-saturated Alfisols of
ecoregion 70b (Cunningham and Ciotkosz, 1984). The boundary between ecoregions 70b and 70a
conforms to the junction between the Perinian Washmgton Formation and the Permian and
Pennsylvanian Waynesboro Formation (Figure 1)
Pittsburgh Low Plateau (70c)
One of Pennsylvania’s most abrupt regional boundaries occurs near the Wisconsinan ice
limit. Here, the muted, till covered terrain of the Erie/Ontario Hills and Lake Plain (61) abuts the
well-dissected Pittsburgh Low Plateau (70c). Ecoregion 70c is characterized by rounded or
knobby hills, narrow valleys, entrenched rivers, fluvial terraces, gently dipping strata, general
farming, land slides, and bituminous coal mining The terrain of ecoregion 70c has a maximum
local relief of 550 feet (168 m) and is more rugged than the Low Lime Drift Plain (61c) and lacks
the folded ridges of the Forested Hills and Mountains (69a). Hilltop elevations commonly range
36
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from 1,200 to 1,300 feet (3 66-396 m), but increase in altitude toward the northeast. Ecoregion
70c is generally lower and less forested than the Unglaciated Allegheny High Plateau (62d), the
Forested Hills and Mountains (69a), or the Uplands and Valleys of Mixed Land Use (69b). The
growing season varies inversely with elevation and ranges from about 170 days near Pittsburgh to
120 days in the northeast
Gilpin, Ernest, Wharton, Upshur, Ernest, Hazieton, Weikert, Cavode, and Rayne soils are
common and are derived primanly from Pennsylvanian sandstone, shale, and coal of the
Conemaugh and Allegheny Groups; they are typically base-poor soils. Udorthents are locally
common and are byproducts of bituminous coal mming. Different soil occur outside of ecoregion
70c which has more Gilpm soils than ecoregion 62d and fewer Alfisols than in the Monongahela
Transition Zone (7Db) or ecoregion 61c.
The natural vegetation of ecoregion 70c was mostly Appalachian oak forest (Cuff and
others, 1989, p. 52). Today, farming is more common in ecoregion 70c than woodland. General
farming and dairy farming predominate, but are often handicapped by the short growing season,
sloping terrain, mining disturbance, soil wetness, and low soil fertility. There are oil wells in the
west and gas fields in the east. Industry and population are concentrated in the Beaver, lower
Allegheny, and Ohio valleys. Widespread bituminous coal mining has left the land barren or
reverting to woodland; some soils that have been reclaimed and releveled are not very satisfactory
for cultivation (Zarichansky and others, 1964, p. 88). Extensive acid mine drainage and industrial
pollution have degraded stream habitat and caused the loss of at least 16 fish species from the
Ohio River drainage of Pennsylvania (Cooper, 1983, p 5).
Figure 1 shows the boundaries of ecoregion 70c. Its western border generally follows the
Wisconsinan ice limit; here terrain, surficial deposits, potential natural vegetation and land use
change markedly The northeastern boundary with the Unglaciated Allegheny High Plateau (62d)
is drawn where elevation, forest density, and soil changes; the Pittsburgh Low Plateau (70c) has
lower elevations, less woodland density, and more Gilpin soils than ecoregion 62d The eastern
boundary between the Central Appalachians (69) and ecoregion 70c is determined primarily by
land use, geology, and elevation; the more densely forested ecoregion 69 is higher, cooler, and
steeper than ecoregion 70c and is underlain by more resistant rock.
37
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DATA
• — .•
i I Q aa1 a g Gr. w,!IdlT.er. emreR ifC.. ..S.fl aye Natsesi
AS S. • Ph y.M grap y S SsuuarDai e e l 80 dws ( I I t..eal Ciap Piadacetas tA udsaa at Iassi . S I Ys s t aUa. I.ad Vs. .ad tu Cater
I (lasi) . ___
oiostly Precambrian graniuc gneiss and - MostIy HapIu ilts, Fragiudults, Dystrochrepls, 44-48 / ppal ach ian oak forest Mosaic dairy-general farms,
iornblende incus; also Cambrian quartaite. Iapludalfs / Mesic / Chester, Glenville, L7O woodland also residential uses.
angIomerates along eastern Reading Hills. lsandywine, Concstoga, Rolliager I Stoniness, Wooded where stony, steep.
-
fostly Fragiaqssepts. Fragiochrepts, Dysteochrept s 33-40 increasing Mostly Appalachian oak forest; i Mouic of cropland/ pastze lam
Mostly mesic, some frigid in northwest I SE I ocne northern hardwood forest and woodland. Daisy fanning
(olusia, Wellsboeo, Morris. Oquaga, Mardin. l 60 in southeast -away from Susquehanna H. at and livestock raising are
.oidatown / Stoniness, low fertility, acidity, declining to 100 bigher elevations. Bogs, marshes impoflant.
Iraina ce ( In the northwest common.
i bIaciated Iand ape Rolling to ‘ 900 1,360 I AoatJy claycy Wisconsinan l lram Till and fre tlyFragiaqualfs also l 1 ragsudalfs I Mesicl 40-42 / orthern hardwood forest, Dasry farming with some’feed
.$aF, Iscady level terrain; flat- often < 150; some outwash, alluvium, loamy till, Sheffield, Plates, Venango, Frenchtown, 140-1 go eech/rnaple forest, also crops; scattered, small woodlota
...: oUomed valleys, lakes, low’ na.x. 360 lacustrine material partly overlie acidic, Cambridgc / Poor drainage, low fertility linarshes and scattered needle- cspecially on poorly drained
bradient stseanis, wetlands Mississippian Devosuan sedimentary rock of leaf evergreen bogs s stes
Jrarnes v yin coarseness
1 11.* )3laciated rolling plains low 51 1002000 Loamy Wiscosisinan Kent till coarse Mostly Fragiaqualfs Fragiudalfs also -‘37-44 / orthern hardwood forest and Mosiic finns more common
WWI L&14j oundsd hills gentle slopes rising eastward outwash material and fine glacial lake Dystrochrepts Fragiocluepts Haphsdalfs (115 170 eechImaple forest Some than woodland despite rather
Jicoad over fit valleys Locally 250-400 5 deposits partly cover flat lying, acidic ragiaqucpta I Messc some frigid I Frenchtown Ap alachian oak forest near ice shoa1 growing season soil
Jiummocky stagnation moismes nrx at ice sedsmentary rock of varying ages and Pienango Ravesaia Cambridge Chenango - limit Scattered prairies 4wetness Dairy faims also hay
utwash landfomu unit in east fcoarsenesses Surficial materials are weakly Canfield Mardisi, Erie Valols Howard / Soil rettlehole bogs and tamarack oats grown Oil gas wells deep
5 1 ,ton 5 tr gwasn habitat
Isciated plateau of relatively g1 800 2,3001 Wisconsinsn areS flllnoian drift partly overlie )ystrochrepts Fragiaquepts Pragiochrepts 44 50! Udominantly northern ‘Mostly forested with many
SIMS ‘ 1gb elevation and low relief often 50 175 iorizontal to mildly deformed Devonian 5 ag hilts I Meaic frigid / Oqusga Lordstown 51125 140 51vacation and suburban
y lakes inaz 525 Msuissippian strati The resistant sandstone ,ackawanna, Wellsboro Swartswood, Mardsn, Cool summers s /developments
sand conglomerate of the Duicannon and Wsabboro Volusia Meckcsville / Stoniness ‘short growing
Poplar Gap-Packerton mconbess of the cidsty wetheas South of Wisconsinan limit. aeason
P atsksll Formation predominate apluduhs Fragiudults Dystrockepts Clymer
S 1 , , U Drifton soils
I ragiochre ts,Dystrochrepts,Fragiaquepts/ 1-50/130-l45
4any lakes High gradient 0-800 Devonian Sandstone ssltstone Catskill fesic frigid I Wurtsboro Mardin Dekalb 1W northern hardwood forest Pvacation and suburban
treams near Delaware H. Trunmers Rock, Mabantango Forinatsosis Volusia, Lordstown, Morris Oquaga I Stoniness fuch kettlehole bog habitat Øevelopments
• l 9 wjertshtv wetnesj
I T’ edisTgh i9i0 2 6 6 óY” early T oiâe erc “ b t chr pts 1&agioch cp’ s ag qi p 33 39 fioo l65 domin t rthern Mosdj rest S c 1
lateau low mountains and hills 51300800 resistant acidic sedimentary strata of mostly l Frigid I Lordetown Mardin Moms Oquaga, Cool short iardwood forest Appalachian minmg in the Blossburg Basin
• amps lakes muted landfornu Misslssippian-Pennsylvanisn age Some (Wellsboro Lackawanna / Acidity low fertility rowiog season ioak forest on periphery Some Some dairy farming
ommon in south Devonian-age rocks stoniness steepness well adapted to bogs marshes, speuce bogs
I ostly unglaciated, pre 1062 600 pearly horizontal to mildly folded, resistant lragiudults Hapludsilts Dystrochrepts I Frigid! 5-44/100 160 Predommantly northern Mostly forested Mt h oil
I:: ... . isconsinan drift In west. fising to NE I ac1dic, seditnaitary strata of Devoni.n- Hazleton, Cookpozt, Dekalb, Clymer, Hartleton, l’recs well sardwood forest with production. Some surface coal
issected plateau with ften 550-700 (Pennsylvanian age Cavode Buchanan Lack Kill, Wharton, Ernest sdapted to cool Appalachian oak forest in soigh minmg in south associated
I ountains hills steep slopes pnax 1 300 on pee Wisconsinan drift Hanover Alvsra I hort growing §and west Scattered bogs stream and ground water
hgr u 3 , CStoDineu 0 low fes slijy steepness acidity eason § 4pollut ion
saciarmi. Dissected hills. Steep l,300-1,800 in Hilltops partly covered by Olean till. Mostl f Dystrocbrepts, Fragiochrepts, Fluvaquents s2-44 /130. - Northàn hardwood forest Mostly forested.
ide slopes high-gradient sorth /450-800 Devonian age sandstone siltstone shale 3/ Mesic I Oquaga Wellsboro Holly Basher Climate affected adapted to cool short growing 51
treams lakes, ponds Catskill Formation Recent alluvium in (Aznot I Steepness stoniness shallowness low by topography jseason Scattered wetlands
, afle ,JferWst y acutst 4 4
III t nglacitect ’?ently rolling i0-60 / sMostly unconsolidated, Quaternary marine Tostly HapludultsThndoaquults Fr*gsudults / 43-45 /175200 .ppaIachian oak forest Mostly urbanized and
erraces occus along tidally usually <35 sediments, alluvium; some Miocene sand, (Mesic / Made land, Howell, Fallsington, tfarine modified gscattered freshwater intertidal industrialized.
sifluenced Delaware H. 5 gravel of Pcnsaukcn Bridgeton Formations JBeltsville Sassafras Butlertown Jlimate S -and brackish marshes
- z -z r-- -
sling, isolated hills o west, bills lailtstone and argillite including Brunswick, HapluduIts, Fluvaquents I Mesic I Abbotistown 51170-180 poultry fruit, vegetable grain
iigber I (Stockton Lockatong, Gettysburg, and New pnowssiansvslle keadmgton Penn Reaville § s/farming SE of Reading small
§30-200 §Ozford Formations Lasudale I Droughtmess s/farms rural residential
51 gsuburbanizatson
! ..:!r .t .JJnglsciated. Deeply dissected, k7Ot)-1 ,400 I
gged hills rounded summits 00 550
laclated plateau Low rolling 3002400/ (Olean Till partly covers nonresistant, nearly
11* gentle slopes low gradient ften 300-500 iorizontal to slightly deformed, Devonian
treams eskers kames ¨sns ip to 820 at age shale siltstone and sandstone Catskill
ttlchole hop lakes 51dusquehanna B. 3and Lock Haven (Chemtaig of New York)
IFormatsons
-rN . .!H.: laciated. Rolling bills of l,4O0—2,70U I 3olean Till partly covers non-resistant, nearly tostly ragiaquepts, ragiothrepts, Dystrochreptz 34-46I ostiy northern hardwood forest Mosaic of woodlots-agricuitize.
te relief angle isolated 130 -6S0 800 iorizontal, Devonian age sandstone siltstone Measc and frigid I Volusia Mardin Wellsboro 130-l40 rith some Appalachian oak 51 Forest cover is more common
ow mountains Small glacial 5 near and shale of the Catskill Formation forns Oquaga Lordstown I Stoniness acidity ‘sforest near the Susquehanna than pasture land.
akes very common Susquehanna eelneu Rsver Bogs and marshes very
., iv ___L —, — —— - ‘ I —
eposff onal lake plain; swales, -790 I Quaternary lake sediments (gravel, sand, silt ostl iapludai?slragiaquepts,Thsmaquepts, 37-42 I 175-194. Beech!maple forest, Great Vineyards, orchards, vegetables,
(lL4 t ach ndçes bay mouth bar §<50 100 and clay) overlie Devonian shale Epiaquepts Epiaquolls I Mesic I Conotton on sL Erie increases iLakes shoreline habitat 4 nussery crops are adapted to
oastal cliffs with slumping § (beach ridges Rinser Wallington Conneaut Intcr snow s/lake shore climate Also urban
Wauseon Birdsall I Local subsoil drainage louds delays and industrial activity
5 4roat. ,.. 51
ardwood forest with
ippalachian oak forest on
outhern periphery. Kettlehole
og habitat common, till
srreiu occur on Illinoian
eoosits in the south
I .__- Ils 5O.650 sconglomerates. Gettysburg arid Hammer Montalto, Mount Lucas, Ungers, Penn, l70-l80 5teep. General farms and
Creek Conglomerates. Brecknock, Nesharniny, Lehigh, I Low fertility, s/pastures elsewhere.
51 1 4toniness steepness 4
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I j U - . . - Ct. .w • • . Gresc Gt. i S It p.mt r* c ja .1 C. .i s1l • • .
I ?b7 $. k.p -. . $O1 tCO R *t44 I (L 6 4 v s (I9U S r1 .JL. Ckop Prc . o. Uailtath. .rRaitrklls.L I • Lzad Un sad L .d Ca,.r
I I : . • • . t&r ) t °l c 1 4 (* *) M i, ai fl9b3 I S,wc ! “i cvL 1$ Dc . t tr & ‘uu 1: d 04Mfl ( 9 )
1 . • • ... . . .. .. - - u w c s*’ C 3a i iad . . y;. isc (I 64 -
II ‘• • • . ::- . . - . t391 . : •:: , : •
!w* t nglsciatcd. Low rounded hills- rt$50.I,050 I wc Paleozoic, Precambrian mctunorpbic Mo,tIy HaplukiIu. Dyitrochtepu I Mesic I $O-46 I iAppalschian oak forest Extcnsive residentisi,
Idges. irregular planis. narrow ften 130-330; snd igneous strats Wissahickon snd Peters Most1y ester Gleneig. Msnor Ehosk I Slope §1 75-200 LocsUy. barrens occ s on commercial, and industrisi
. Il leyL naI. 590 Crcck schists common; local gneiu. steepneu erpe1itme o icrops. sctivity ness Philadelphia.
. ___________ . e f ms common
.‘• * n lac sted. ‘ (easly level to 325—675 I MostJy Ordovician limestone of the Mostly Hapludalfa; also Hapludulta. Eufroc&epts 4l-45 I fosUy Appalachian oak forest Extensive general, corn, hay,
DII. H* lating. fertile valleys. 3O -.-125 Conestoga Formation; also Ordovician J Mesic I Duffield, Hageritown, Letoet, Pequea, l7O-l9O jSome osk/hickoxy/pine forest dsiry, livestock, tobacco
45 ( 4 I doloinite aDd shale and Cambrian carbonatca. Concstogs, Bcdüigton. 2 ilong Susquchanna River. farming. Residential arcs
,$ .J : : : 4 lncreulng.
. ;;;L• ;It fl Th• y r r i r-
1u4;P ru . gaps-coves. Ridges steep d$ 3 ,75O highest igneous rock. VA: basalt, metabualt of the HapIu&dts I Mesic I CatOctin, Myersville, southwsrd I 150- Localized dairying, poultry
! • • cli dissected. n south I Catoctin Formation; granite and grsnodioritc HayesviUc, Arcndtsville I Low fertility, acidity. l75; less frost rsising; orchards arc found on
n1a I. 1,300; of the Virginia Blue Ridge Complcx stooincss. steepness ftcqucncy in tbe Arcndtsvillc soils.
- . eit t la ndeaite, ft and ce tone of the S ft un oothills.
: -:. : . outh Fonnation. PA.: mct.rhyolite-inetabssah.
-: iMfl diabase metabasalt . metarhvolite
4I
g
AppsIachinoak forest ExtcnsiveIy forested
loping ridges, deep-nw-row -3 ,5O0, highest rock of the Weverton-Loudon, Antietam, Hapludaifs I Mesic I Laidig, Wallen, Dekaib. o south I
alleys. n sot*h / Harpcrs Formations (Erwin, Hampton Lily, Beaks, Welkert; Edgemont, Highfield / I50-l75; less frost
. 1,000 es tively in Virginia) 10w! il nfoothills.
oglaciatet Hilly high plateau, ,600-4,500 I recambrian metamorphic rock, including Dystrocbrepts, Hapludalfo; also Ultisols I Mcsic I About 39 I Appalacbian oak forest, ,Often wooded Some dairy:
altered nsonadnocks. New ltiver$cn under 200 uartzite, graywacke, conglomerate of the Chester , Hayesville, Glenclg. Manor Mycriville 75 .k(hickory/pine forest. livestock pastures and apple
ot incised. ynclsburg Formation. Also gneiss, schist, - Stoniness, ahallo meu orch ards.
uartsite. /
oglaciated. High ridges, p,600 -5 ,728 on aleozoic rhyolite porphyry, srkose, thft Mt. Dyatrochrcpts. Hapludults / Mesic / Hayesvillc, About 42 / AppaJacbisn oak forest and Extcnsive forest cover.
ountains; wdll dissected, steep vft Rogers I gets Volcanic Group; Precambrian Virgi soi4Grimsley, Porters I Stoniness, steepness 60-170 somc northern hardwood forest I
lopez. pften 1,150- lire Ridge Complex; phyllite. quartzlte, t high clcvations.
1,500 jraywacke, conglomerate: Lyncbburg
Formation.
- -. -.
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nglaciated high, steep ridges; p,600 -4,425 Cambrian sedimentary and nretasedimentsry Mostly Dystrochrepts I Mesic / Beaks, elkert, About 42 / Appalachian oak forest and Extensively forested.
ep, narrow valleys. 00-1,i50 {rock. Sandstone-quartzite form crests; shale, Dekalb, Wallen. l60-l70 rome northern hardwood forest
J ,hyllite, siltstone, sandstone form side slope j , j t high elevations.
e t 7oT Tu ’aZ aTfs T a e
evel to undulating valleys. wcstward/ Ordovican, and Cambrian limestone, H.pludults, Paleudults I Mesic 7 H.agcrstown 145-180 in north and oak/hickoey/pine on steep sites. Local
altered low ridges, kant 50-500 dolomite, and calcareous shale. conunon locally orest in south. urbsn/suburban development
cream. . -
ng exceptnortiscut
oIling valleys, isolated hills. 50-S00 and fine grained sandstones of the Hamilton, 030-lEO Osut oak/hickory/pine forest in uses. Wooded where steep or
Hasnpshire, Brallier, Chemung Formations, -‘ outh. 5poorly drained.
- - - - -
n elated except in northeast l,000-4,)00 / Clinton Grot and Tuscarora, ‘ocouo, Bald Dy*trochrepto, Fragiudults/ Mule I Dekalb, 6-50 I $ostly Appalachian oak forest Forestcd.
harp, folded ridges, narrow 100-l,500 -Eagle Formations common. Paleozoic Laidig, Beaks, Welkeet, Lehew I Steepness, 20-l80 in north, oak/hickory/pine forest
alleys. sandstone and conglomerate form crests; roniriess 3n south. I
- — - . .,- -.- - - - ----. -- - - - ---.. ..
nglaciated except northeast. 00-4,15O I st1y interbedded, folded-faulted bevonian Mostly Dysliochrcpts / Mesic 1 Dekalb, Bests, 36-44 I ostly Appalachian oak jorest itly or t i: me pastures.
iuected ridges and knobs, 00-1,l50 (sediinentary rock including siltstorres. Lock Weikert, Lehew 120-180 in north, oak/hickory/pine forest
enulated contours. Valleys Havcn, Chemung, Trimmers Rock, Scalier, in south.
roader than ccor ion 67c. ,, Hasnjshire Formations and Chemu Groiji.
trip mined terrain. Extcsn al;sthstoiie.
- areas and stream pnax. 600 conglomerate, anthracite coal. Llewellyn Fragiudu1ts I Mesic I Dekalb, Hazleton l40-160 with some northern hardwood ground, and urban-industrial
e
nglaciated. Valleys, low ridges, 11,640-3,200 I Predominantly folded and faulted Ordovican Most1y Hapludalfs, Paleudalfs, Fragiudults, 04-45 I efost1y Appalachian oak forest. Øntensively farmed; woodland
st terrain. I50-500 .‘.nd Cambrian limestone, dolomite and Paleudults / Mesic. 175-l80 I whcrc steep. Local urban!
calcareous shale. suburban development.
I I :/
.. -..... —.. ....-..--
oglaciated. Rolling valleys with l,3O0-2,500; ICambrian through Mississippian iraerbeddrd lDystrochrepts, Hapludults, Fragiixtults; some 44-45 I 9sfostly Appalachian oak forest iarm, urban, or suburban uses.
ills. ç iighcr knobsi shales, siltstoncs; sandstone, limestone too. HapludelfsJ Mesic 375-180 I IWoodlots occur in steep or
5-650 Brallier, Rome, Elbrook, Chemung. Clinton I : poorly drained areas.
- ..L.. .. . -. - --. ---.-. -.. -- - ---...- --. -.. —. - - - -..
nglaciated Sharp crested foIded 2,300-3,450 I Ridge forming strata: Paleozoac sandstone, Dystrockepts, Fragiudults I Mcsic I Bests, 44-45 / 9 ,fostly Appalachian oak forest. iForcstet
- es, narrow valleys. 00-1,500 onglomerate. Weaker rock form slopes. Dckalb, Weikert, Laidig/ Steepness, stoniness l70-i75
nglaciateeL olded, dissected, 2,lO0-4,lS0 Mostly Devonian, scene Ordovician, strocbrepts. Fragiudults I Mesic / Welkcgt, 44-45 1 sfostIy Appalachian oak forest MostIy forested. Some pastures
oisadcd knobi and ridges. 50-800 Cambrian interbcddcd sedimentary rock erka, Laidig, Wallen l70-l75 on wider floodplains.
enuisted contours. Valleys - luding siltstones. Chemung, Brallier
than ecore ion 6Th. ormstions common. I I
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J3 4 Gaal.av t Grautt aqsitm ta naaasaLgSat cawaalati 4 (sMthepey 14 : .1
Pkp laf fly vaaiw * 5 , 5 cc g . sØsaØ i sa 3..s# Q.flt.sith. fs Map ka * usntaas t Yqe tado J,aa4 11$ ;S 14a4 Ca ’.
Ocuws at (INS t M t s U*11S6$ I 4sss’ t ate a4 st 1 4 DseazSst t lzsls Cnfl s I I sa C m ni l s i M m tI959t
W A H bn (Ut , 5 S. bs P .md t ka (sen*yrayr an Was$c ( 1 144)
sglaciated. Dissected, rugged l,SO0-3,OO0; ‘rbnsrily sandstone; also conglomnate lapludults, Fragiut ts lts, Dyslroclsrepts, 3 S -60/ Appalachian oak, northern fl&xtensive forests. Gas wells and
Is, mountains, ndges with sax. 4,600/ hale, and coal. Pennsylvanian Potlsville Fraginchrepts, T taptaquepts / Frigid and enesic / ?13 5-l65 iardwood , mixed mesophytic ‘ bitusninnus coal mines are
ow valleys. Deeply incised §‘c130-l,9S0 koup. Pennsylvanian Allegheny Group, Steepness, stoniness, dryness (is sandy areas) goresis. Noetheastern spruce/fir locally common; associated
ocally. High-gradient steams thssissippian Poenno and Mauch Chunk (forest where very high and cool; ptreain and land degradation
waterfalls occur. 7 omsations occur. sceub oak where sandy. occurs. Scattered agriculture.
Scattered glades (sphagnum
—.. -.. . .. - . .-. -- —. - — — — — — — 3 1 SL !PLYfSW 34 ,, ,
nglaciated. Rounded hills, low l,375-2,SO0/ Jhale, sittutone, sandstone, some coal. tapludults, Fzagiuttilti, Dysirochrepts / Mesic / l7-50/ App a lachian oak, northern Farms interspersed with
cs on upland plateau. <5O-1,0O0 ‘ennsylvanian Concmaugh and Allegheny l l pin, Ernest, Whartno, Rayne, Clymcr, l20-l65 i3sardwood, mixed mesopbytic froodland. Widespread
iroups common. )ckalh, Cookporl Hazleton, Udorthents / Low frorests. Scattered sphagnum bituminous coal minin, mine
ferti lity wetness moss black spruce and spot ls stream degradation.
— sarnarackgladcs
sg laciatet Rolling karst ,S00-2 5 nmarily ISestons and shale of doatiy lhphsthdte, PaIaido , lh udalft, p 5-40 / OakThicko r y forest. cBluepasa pasture, some gene r ul
andscape with sinkholes, c150-650; max. t&ississippian age. Greenbrier Group and )ystroc&epts I Mm i x / Frederick, Frankstown, l49-165 ffarmmg; wooded hills. Beef
ground drasnag low atream l 000 along llucfi Id Formation common, some Veatmoreland, Litz, 6 51pm Calv i (often high- cattle sheep poultry raising
sty strongly flowmg sprmgs sGreenbrser K tccrady Formation base substratum) smportant some dasrymg
lated rounded hilts Fodder crops ncludmg corn
, .,.
sglaclatcct Dissected hills, t,200-3,600 I pennsylvanian sandstone, siltstone, shale, and Waptudulb, Dyatrochrepts I Mesic / Cl xner- f44-4g / Mostly mixed mesnpbytic threst rMos’tly torestett kxtrnsive coal
otmtains, ridges, steep slopes, p50-550 coal of the Pottsville Group and Allegheny tDekalh-Jefferson / Steepness, stoniness, g 170- 185 mining, logging, stream
my narrow ridgetops. Wormation. shallowness degradation. Livestock farms in
I } wider valleys. Scattered towns,
_ _ 4 , g we -
ngtaitfl. Rounded hills l,t75-l7O0 / Prrmian sandstone, shale, limestone, coal of MoIy”Tiapludalfs; some Fluvaquents / Meaic’ 7 3S-42 / Appalachian oak forest; mixed Moatic; motflorests-wosdtots
ning to ridges. Scattered 000—550 Greene and Washington Formations. Dorniont, Culleoka, Newark / Heavy clay l40-l60 mesophytic forest Øhan crcpland-pasttxcs.
an lips subsoil steepness landslips 4 l iituminous coal mining, oil gas
S ?wells
nglaciated. Rounded hills and ,200-l,300 / ersnian and Pennsylvanian sandstone shale Mostly Hapludalfa some Fluvaquents Udorihen4fl6-4l I !Appalachian oak forest some Urban suburban, Inebisirial
idges, accordant summits. 00-350 inmestone, coal of the Waynesboro Formation Mesic / Guernsey, Donnont, Culteoks, l50-t70 )nised mesophytic forest in /activity; some woodland,
tips occur. md Monongahela Group. Westmoreland, Newark / Steepness, tsndstipa ,outh gcneral farms, bituminous coal
. . . . & , S w M, .Mr,cam 4pMp4Ation
isg laciated except in the flen 1,100- Mostly Pennsylvanian sandstone, shale, Mostly Hapludu lts, Fraiudulta, Dystrochrtpts, ,,3646/ 120-170. IjAppalachian oak forest; scene GencraI farming, pastures Som
stremne northwest Rounded 1,400; max. iiltstone, coal. Common are the Casselman Udorthents / Mesic / Gilpin, Ernest, Wharton, y nised mesophytic forest in froodland, bituminous coat
ills, narrow valleys. ,000 / 0 nd Gtenshaw Formations. The Allegheny Haxteton, Weikert, Cavode, Rayne / Low outh mines, oil -gas wells, and
bout 500-550 rnup and others are exposed in valleys and fertility assnciated stream degradation.
ósthenoith. S
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Figure 1.
Level III and IV Ecoregions of Pennsylvania and the Blue Ridge Mountains,
Ridge and Valley, and Central Appalachians of EPA Region 3
58 NORTHEASTERN HIGHLANDS
El 58h Reading Prong
60 NORTHERN APPALACHIAN PLATEAU
El 60a Glaciated Low Plateau
El BOb Northeastern Uplands
El
D
61 ER$EFONTARIO HILLS AND LAKE PLAIN
61a Erie Lake Plain
61b Mosquito Creok-Pymatuning Lowlands
61c Low Lime Till Plain
62 NORTH CENTRAL APPALACHIANS
62a Pocono High Plateau
— 62b Low Poconos
— 62c Glaciated Allegheny High Plateau
— 62d Unglaciated Allegheny High Plateau
— 62e Low Catskills
63 MIDDLE ATLANTIC COASTAL PLAIN
El 63a Delaware River Terraces and Uplands
64 NORTHERN PIEDMONT
E. 64a Triassic Lowlands
64b Diabase and Conglomerate Uplands
64c Piedmont Uplands
— 64d Piedmont Limestone/Dokxnite Lowlands
65 SOUTHEASTERN PLAINS
66 BLUE RIDGE MOUNTAINS
— BBs Northern Igneous Ridges
D 66b Northern Sedimentary-
Metasedimentary Ridges
El 66c InterIor Plateau
— 66d Southern Igneous Ridges
and Mountains
66e Southern Sedimentary
RIdges
— L.vullllBoundsry
L,v IV 8o tidwy
s —
Cc —
/ 1
A
F
7 -
‘1
I
67 RIDGE AND VALLEY
67a Northern Llmestcn&Dolcmite Valley
El 6Th Northern Shale Valleys
El 67c Northern Sandstone Ridges
• Bid Northern Dissected Ridges
— 67e Anthracite
• 671 Southern Umeston&Dólornite Valleys and Low
Rolling Hills
[ :.. Big Southern Shale Valleys
[ 6Th Southern Sandstone Ridges
— 671 Southern Dissected Ridges and Knobs
69 CENTRAL APPALACHIANS
69a Forested Hills and Mountains
69b Uplands and Valleys of Mixed Land Use
69c Greenbrler Karat
69d Cumberland MountaIns
70 WESTERN ALLEGHENY PLATEAU
lOs Permian Hills
7Gb Monongahela Transition Zone
70c Pittsburgh Low Plateau
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