United States
Environmental Protection
Agency
NHEERL EPA/600R-96/007
Western Ecology Division June 1996
Corvallis OR 97333
Research and Development
LEVEL III AND IV ECOREGIONS
T} p A OF PENNSYLVANIA AND THE BLUE
^ A RIDGE MOUNTAINS, THE RIDGE
AND VALLEY, AND THE CONTRAL
APPALACHIANS OF VIRGINIA,
WEST VIRGINIA AND MARYLAND
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LEVEL ffl AND IV ECOREGIONS OF PENNSYLVANIA AND THE BLUE RIDGE
MOUNTAINS, THE RIDGE AND VALLEY,
AND THE CENTRAL APPALACHIANS OF VIRGINIA, WEST VIRGINIA,
AND MARYLAND
by
Alan J. Woods'
James M. Omernik1
Douglas D. Brown3
Chris W. Kiilsgaard4
EPA/600/R-96/077
June 30,1996
U.S. Environmental Protection Agency
National Health and Environmental Effects Research Laboratory
200 SW 35th Street
Corvallis, Oregon 97333
The information in this document has been funded wholly by
the U.S. 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.
'Dynamic Corporation
U.S. EPA National Health and Environmental Effects Research Laboratory
200 SW 35th Street
Corvallis, Oregon 97333
'U.S. Environmental Protection Agency
National Health and Environmental Effects Research Laboratory
200 SW 35th Street
Corvallis, Oregon 97333
®U.S. Forest Service
Rocky Mountain Forest and Range Experiment Station
240 Prospect Rd.
Ft. Collins, Colorado 80526
'Oregon Department of Fish and Wildlife
7118 NE Vanderfcerg Av.
Corvallis, 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
Erie/Ontario Hills and Lake Plain (61) 7
Erie Lake Plain (61a) 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 Plain (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 Metasedimentaiy Ridges (66b) 23
Interior Plateau (66c) 23
Southern Igneous Ridges and Mountains (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 (67f) 28
Southern Shale Valleys (67g) 29
Southern Sandstone Ridges (67h) 29
Southern Dissected Ridges (6Ti) 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
Permian 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 Pennsylvania and the Blue Ridge 50
Mountains, Ridge and Valley, and Central Appalachians of EPA
Region 3
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LEVEL m 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, monitoring, 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 in the existing and attainable quality of
environmental resources. They have proven to be an effective aid for inventorying and assessing
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 Advisoiy Board, 1991; Wany and Hanau, 1993).
Ecoregion frameworks have been developed for the United States (Bailey, 1976, 1983;
Bailey and others, 1994; Omemik, 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 American ecoregion
frameworks have evolved considerably in recent years (Bailey, 1995; Bailey and others, 1985;
Omemik, 1995a; Omemik 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, 1995b).
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 integrity (Wiken,
1986; Omernik, 1995a). These phenomena include geology, physiography, vegetation, climate,
soils, land use, wildlife, and hydrology. We do not begin by treating any one phenomena with
more-weight than any other. Rather, we lode for patterns of coincidence between geographic
phenomena that cause or reflect differences in ecosystem characteristics. The relative importance
of each factor 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 m, the continental United States contains 98 ecoregions.
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Level IV ecological regions are further subdivisions of level m units. 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
(Plotnikoff, 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, in
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 refined level m ecoregions and delineated the more detailed level IV
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 m
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 ecoregicmalization 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
these efforts have involved the use of indices of water quality and biotic integrity (IBI) (Hughes,
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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 (DEI) (Omernik, 1995a,
1995b); although an IEI 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 procedures used to accomplish the regionalization process followed that of
similar ecoregion projects (Griffith and others, 1994a, 1994b, 1994c) and consisted of compiling
and reviewing relevant materials, maps, and data; outlining regional characteristics; drafting level
in 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. In 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 die 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 Omemik (1995a), Qmeraik 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, (S) potential natural vegetation, (6) soil, (7) structural/bedrock
geology, and (8) surficial/Quaternary 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), Kuchler
(1964), and county soils surveys (USDA - NRCS). Seal information came from regional
overviews {Ciolkosz and Dobos, 1989, Cunningham.and Ciolkosz, 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 - NRCS). Geological
information came from Beqg 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 m 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 m ecoregions and 37 level IV
ecoregions. Many of the boundaries of these ecoregions are transitional, and die ecoregion map
(Figure 1) should be interpreted with that in mind. Ecoregion descriptions follow and include
differentiating criteria; their detail varies 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 Wemersville Ridge in northeastern Pennsylvania. On the ecoregion map
(Figure 1), the Northeastern Highlands (58) contains one level IV ecoregion: the Reading Prong
(58h).
The Reading Prong (58h) is contiguous with die 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 200-5S0 feet (61-168 m) above the intervening valleys. Maximum
elevation, about 1,400 feet (427 m), occurs on the Cambrian quartzite knobs of Wemersville
Ridge. Elsewhere, Precambrian granitic gneiss, Precambrian hornblende gneiss, and fan glomerate
are common (Berg and others, 1980). The metamorphic and igneous rocks are covered by slightly
acidic, 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 only 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, nigged, crystalline hills are
higher and both physiographically different and lithologically distinct from ecoregions 64a, 64d,
and 67a.
Northern Appalachian Plateau and Uplands (60)
Ecoregion 60, in northeastern Pennsylvania, 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 dadated 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 derived from till and are mostly mesic Inceptisols
(Cunningham and Ciolkosz, 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 Susquehanna River at higher elevations; dominant trees included
sugar maple (Acer saccharvm), yellow birch (Betula allegheniensis), beech (Fagus grandifolia),
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 mare nigged 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 characteristics 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 (91-153 m). The growing
season varies inversely with elevation, increasing from 100 days in the northwest to 160 days in
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, Dystrochrepts) developed on
the drift deposits (Cunningham and Ciolkosz, 1984). Leached and stony, they commonly have
fragipans and poor drainage.
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 dairy-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 sane 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 ecoregian
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 in 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 angje, elevation, channel gradient, and the ratio of woodland to farmland; all these are
greater in ecoregion 60b than in ecoregion 60a
Ecoregion 60b is a dissected and glaciated plateau characterized by low, rolling 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 (427-610 m), increasing to a
maximum of approximately 2,700 feet (823 m) at Ml 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 platyrhynchos),
Canada geese (Branta canadensis), wood ducks (Aix sponsa), and the American bittern (Botaurus
Ientiginosus), which is threatened in Pennsylvania (Gill, 1985, p. 310).
The Inceptisols (Fragiaquepts, Fragiochrepts, Dystrochrepts) of ecoregion 60b are
derived from Wisconsinan drift and often suffer from poor drainage and stoniness (Cunningham
and Ciolkosz, 1984; Higbee, 1967). The soil, climate, and terrain of ecoregion 60b support a
largo* 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 declined 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, 1990-1991, 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 in 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 in 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 Morris-Wellsboro and Monis-Wellsboro-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 nigged and wooded than
ecoregion 60b. The southern boundary between ecoregions 60b and die Low Poconos (62b)
occurs at the forest density break shown on the Scranton 1:2S0,000-scale topographic map;
ecoregion 62b is more wooded than ecoregion 60b. In places, the border also follows the
lithologjcal break between coarser and finer 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 railing
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 relief 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 Erie to 2,000 feet (609 m) inland.
The most common soils are Alfisols and Inceptisols; they tend to be acidic and are
derived mainly from till and lacustrine material. 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 granchfolia), elsewhere, northern hardwood forest occurred, with
sugar maple (Acer saccharum), yellow birch (Betula allegheniensis), beech (Fagus grcmdifolia),
and hemlock (Tsuga canadensis) as dominant trees (Cuff and others, 1989, p. 52).
The Erie/Ontario Hills 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 dairy fanning.
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 limit 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 Piain (61a)
The narrow Erie Lake Plain (61a) is characterized by nearly level terrain, lacustrine
deposits, a lake-modified climate, and distinctive crops. Island 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 SO 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-lOweeks 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 maturing 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 (Castanea dentata)
grew on gravelly soils (Hicks, 1934). Shoreline vegetation also occurred and is best preserved on
the sandy beaches, dunes, and flats of Presque Isle, which shelters Erie harbor. Here grows
vegetation such as sea rocket (Cakile edentula), beach grass (.Ammophilia breviligulata), 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 exdis
exilis) and regal fritillary (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-Quaternary shoreline; to the north of this line, lacustrine deposits
begin, natural vegetation changes, and the climate moderates.
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Mosquito Creek-Pymatuni ng Lowlands (61b)
The glaciated Mosquito Creek-Pymatuni ng 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 lacustrine
deposits. Numerous wetlands and broad, flat-bottomed valleys occur on the silt and silty clayey
loams. Low-gradient streams are common, have few riffles, 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-drained 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
(Phragmites communis) (Brenner, 1985, p. 11). Shrub swamps and swamp forests cover large
areas of the Mosquito Creek-Pymatuning Lowlands (61b) 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 (Rosapalustris), poison sumac (Rhus vernix), and silky
dogwood (iCornus ammomum). Swamp forests contain species such as red maple (Acer
rubrum), white pine (Pmus 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 km2) in area (Erdman and Wiegman, 1974, p.
13).
The northern bald eagle (Haliaeetus leucocephalus alascanus) and the marsh-dwelling king
rail (Rallus elegcms elegcms) (Gill, 1985, pp. 301-304), endangered in Pennsylvania, inhabit the
Mosquito Creek-Pymatuni ng Lowlands (61b). Several species threatened in Pennsylvania are
also found in die marshes and lakes of ecoregion 61b, including the least bittern (Ixobrychus exilis
exffis\ the American bittern (Botaurus lentiginosus), and the black tern (ChJidonias rdger
surinamensis) (Gill, 1985, pp. 307-314).
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-Pymatuning 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 (61c)
The glaciated Low Lime Drift Plain (61c) 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 floating peat mat of sphagnum, sedges (Carex spp), and sundew
(Drosera rotundifolia), 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 61c, the
Kalm's lobelia (Lobelia kabnii) and the spreading 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 {Ammocrypta
pellucida) and the northern brook lamprey (Ichthyomyzon fossor) (Cooper, 1985, pp. 179,182).
Figure 1 shows the boundaries of the Low Lime Drift Plain (61c). To the east, ecoregion
61c extends to the approximate Wisconsinan ice limit, whereupon the potential natural vegetation
changes, dairy fanning 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 61c abuts
the Erie Lake Plain (61a); hoe 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 north central and northeastern Pennsylvania, is part of a vast, elevated
plateau composed of horizontally bedded sandstone, shale, 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 SO inches (84-127 cm) and there can be as few as 100 days without
killing frost, the shortest period in Pennsylvania. Soils are often frigid and were derived from
residuum, colluvium, 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 Erie/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 originally lacked the beech/maple 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 IV ecoregions: the Pocono High Plateau (62a), the Low Poconos (62b), the Glaciated
Allegheny High Plateau (62c), the UngiLaciated Allegheny High Plateau (62d), and the Low
Catskills (62e). Each is forested and each is underiain by nearly horizontal rock, predominantly
sandstone. Descriptions 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, non carbon ate strata. Elevations are great
enough to make ecoregion 62a higher and coder than the nearby lowlands Glacial advances and
retreats have smoothed die terrain, disrupted drainage, produced hummocky marainal
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, lllinoian 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 orver 300 feet (91 m) high marks the juncture between ecoregions 62a and
62b and their respective lithologies. High-gradient streams and a few waterfalls, such as Indian
Ladder Falls, occur on die escaipment (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, tourist 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
325-140 days reinforces this situation and, therefore, almost no commercially viable fanning
occurs in ecoregion 62a. Limited areas are underlain by Ulinoian 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 (Murphy and Murphy; 1937, p. 364). 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 forest/spruce still
occurs in Hickory Run State Park (Brenner, 1985, p. 14; Erdman and Wiegman, 1974, p. 63).
Wetlands are widespread and include marshes and swamps such as those in Gouldsboro State
Park and along Two Mile Run. Numerous kettiehole bogs occur, including 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, adj acent 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 angustifolia), 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 in 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 Escaipment 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 relief
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 oveilie 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 in ecoregion 62b: They are derived from Wisconsinan drift 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 like those of the Stillwater Natural Area and
swamps such as Saw Creek Headwaters Swamp, Nebo Swamp, Bald Hill Swamp, TannersviUe
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 (Clemmys muhlenbergii) is found in the marshy meadows and sphagnum bogs of
Monroe County and is endangered in Pennsylvania (McCoy, 1985, p. 272). Hie king rail {Rallus
elegans elegans) is found in the marshes of Monroe County and is also endangered in
Pennsylvania (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 forma-. Hilltop elevations are commonly 1,900-
2,300 feet (579-701 m), which is high enough to ensure a short growing season of 100-165 days.
Local relief is about 300-700 feet (91-213 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 (Ciolkosz, 1989; Cunningham and Ciolkosz, 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 intermixed 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 Luzerne County contains approximately 2,000 acres of
virgin northern hardwood forest, as well as numerous hemlock swamps (Erdman and Wiegman,
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 Wisconsiaan 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 surfidal rock than ecoregion 62c. The southern boundary is drawn along
Huckleberry 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 nigged with steep valley sides, entrenched streams, high-
gradient channels, and many waterfalls. Local relief is typically 550-700 feet (168-213 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 (518-671 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 legging
and burning removed most of the natural vegetation during 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 (as reported by Cuff
and others, 1989, p. 53; Erdman and Wiegman, 1974; 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 die Glaciated Allegheny
High Plateau (62c) is at the limit of the (Mean till of Wisconsinan age. The southeastern border is
drawn 3-6 miles (5-10 km) 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 S miles (8
km) wide in northeastern Pennsylvania. Here, the Delaware River has deeply entrenched 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 nigged
for this part of the commonwealth and local relief ranges from about 4S0 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, low 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). Sane wetland vegetation
occurs on poorly drained sites, and northern rock plants grow on the Delaware River cliffs in
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 Geoigia 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 IV
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 influenced.
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 die 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 remaining freshwater intertidal marshes of ecoregion 63a are home to globally
rare species; this habitat is severely endangered in Pennsylvania and the state's only extinct
plant, Micranthemum micranthemoides, was found there (R. Latham, Department of Geology,
University of Pennsylvania, written communication, 1995). Wetlands between Andalusia and
Bristol, including Neshaminy State Park, are reported to contain several plant species endangered
in Pennsylvania, including the arrowhead (Sagittaria cafycina), coast violet (Viola brittoniana),
river bank quill wort (Isoetes riparia), and swamp beggar-ticks (Bidens bidentoides) (Wiegman,
1985, pp. 44-48,66-67, 74). The freshwater intertidal and saltwater Unicum 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 rvbriventris), bog turtle (CUmmys muhlenbergii), king rail (Rallus elegans elegans),
and short-eared owl (Asio flammeus flammeus) (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 (Jxobrychus exilis exilis) and
the American bittern (Botaurus lentiginosus), which are threatened in Pennsylvania (Geyer and
Bolles, 1979, p. 469; Gill, 1985, pp. 307-310).
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 sayartus), the mud sunfish
(Acantharchus pomotis), the blackbanded sunfish (Etmeaeanthus chaetodori), and the swamp
darter (Ertheostoma jusiforme) 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 Genelg soil associations with the Howell
and Fallsington soil associations (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 framed 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 pine (Pirtus virginiana), pitch pine (Pimts rigida),
chestnut oak (Quercus prinus), white oak (Quercus alba), and blade oak (Quercus velutina)
17
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(Cuff and others, 19S9, 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 high base-saturation. 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 Line. 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
IV ecoregions: the Triassic 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.
Triassic Lowlands (64a)
Ecoregion 64a is a plain underlain by sedimentary rock of Triassic age. Its low rolling
hills and broad valleys have a local relief of only 30-200 feet (9-61 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 Iowa- than either the Piedmont Uplands (64c) or the Diabase and Conglomerate Uplands
(64b).
The soils of ecoregion 64a 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; Kuhl 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 platyrhynckos), Canada
geese (Branta canadensis), wood ducks (Aix sponsa), and blade ducks (Anas rvbripes) 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 kabnt) and
the bog turtle (Clemmys muhlenbergii), both endangered in Pennsylvania (McCoy, 1985, pp.
261,270).
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The boundaries of ecoregjon 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 ecoregjon 64b. They rise abruptly from the surrounding lowlands and are often
wooded, rocky, and steep. Crestal elevations are typically 450-1,150 feet (137-351 m), but in
the Conewago Mountains, they rise 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 Triassic 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 originally 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 Gen,
Wildcat Run, Counselman Run, Kelly Run, Femcliff Run, and Oakland Run (Geyer and Bolles,
1979; pp. 442-465; Guilday, 1985, p. 19).
M$tamorphic 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
Chickies, Antietam, and Harpers Formations form the highest areas, the Pigeon Hills and Hdlam
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 GeneJg 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, chromium, and nickel.
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 cod, very
rugged Otter Creek gorge, where virgin chestnut oak (Quercus prinus), hemlock (Tsuga
canadensis), beech (Fagus grandifolia\ sugar maple (Acer saccharum), and basswood (7Ilia
heterophylla) still grow (Erdman and Wiegman, 1974, p. 98).
Scattered serpentine barrens occur on chrome soils and support a specialized vegetation
composed of dry oak/pine forests (e.g., Quercus marilandica, Q. stettata, Q. velutma, Pirtus
virgmiana), greenbrier (Smilax rotundifolia), prairie grasses (e.g., Schizachyrivm scoparius,
Sporobolus heterolepis), and herbs (e.g., Aster depauperatus, Cerastium arvense var.
villossissimum, Talinum teretifolnmi) (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 (Hemileuca mcda) occurs only in the
serpentine barrens and is threatened in Pennsylvania (Opler, 1985, p. 88). Pitch pine (Pirtus
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 (R. Latham,
Department of Geology, University of Pennsylvania, written communication, 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, Wilmington, and the major
transportation corridors. 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 Precambrian
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 disappearing streams. Elevations are lower than adjacent
ecoregions, typically 32S-S2S 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 limestone of the Conestoga Formation predominates. It is a high yielding
aquifer riddled with solution channels that reduce water filtration; as a result, groundwater is
sometimes contaminated. Other Ordovician and Cambrian Formations occur and contain
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 die 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, including deisner's
Swamp near Quarryville, the type locality of the bog turtle (Clemmys muhlenbergii), which is
endangered in Pennsylvania (Erdman and Wiegman, 1974, p. 96).
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 eastern United States
(Cuff and others, 1989, p. 20). It is one of the most productive agricultural areas in Pennsylvania
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 in 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 expanding, 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 die 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 dear and have many riffle sections; they support a different, less
diverse fi§h m««nbl*ge than the streams of die 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 varies significantly. Generally, both growing season and precipitation increase
southward. The frost-free period varies from less than ISO 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 Mountains 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,
agricultural lowlands of the Northern Limestone/Dolomite Valleys (67a), the Southern
Limestone/Dolomite Valleys and Low Rolling Hills (67f), the Southern Shale Valleys (67gX and
the Triassic Lowlands (64a).
Northern Igneous Ridges (66a)
Ecoregion 66a extends southwestward from South Mountain, 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 m^ximumdj^o^er 3,750 feet (1,143 m). Local relief
also increases southward to a maximum of about 1,300 feet£396 m).
Precambrian and Paleozoic metavolcahic-antMgneous rock underlie ecoregion 66a
Typically occurring in Vugini& 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 sedimentaiy-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 sloping ridges and deep, narrow valleys. Crestal elevations
typically rise 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 readies 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 Virginia), and Harpers (Hampton in
Virginia) Formations are common. Typically, Inceptisols, Ultisols, and Alfisols developed from
the bedrock. Laidig, Wallen, Dekalb, Lily, Berks, and Weikert soils are widespread. Stoniness,
steepness, low fertility, and acidity are characteristics 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 Metasedimentary 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 Precambrian 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 characteristics of these soils.
The natural vegetation was Appalachian oak forest and oak/hickory/pine forest (Kuchler,
1964). Today, the Interior Plateau (66c) has woodlots interspersed with pastures. Dairy and
livestock farms are common and some apple orchards also occur. Woodland remains 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 tot 1,500 feet 1351-457
tn). V y
Precambrian and Paleozoic rock underlies ecoregion 66d. The MtNRo^ers Volcanic
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 (Kuchler, 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
Metasedimentary Ridges ecoregion (66b). Local relief ranges from about 500 to 1,150 feet (152-
351 m).
Cambrian 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 (Kuchler, 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 alternating 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 reliefvaries 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 die 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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Lithoiogical characteristics often determine surface morphology. Many ridges are formed on
well-cemented, relatively resistant material such as sandstone or conglomerate; they are often
rather parallel and alternate with valleys but, in 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
common 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 {ran
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 die swift, actively
down-cutting streams which run off steep ridges must join the gentle valleys perpendicularly.
Other larger rivers such as the Susquehanna River cross structure, cutting deep gorges through
ridges in the process. High-gradient streams are common in watergaps and on ridge slopes;
elsewhere, gender 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 Rid|ge and Valley (67) was dominated by Appalachian oak
forest. Southward, oak/hickory/pine forest was common to about die James River, whereupon
the Appalachian oak forest returned (Kuchler, 1964). Hemlock (Tsuga canadensis), along with a
mixture of white pine (Pinus strobus), beech (Fagus granthfoha), 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 on). Loudly,
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), die Ridge and Valley (67) is composed of 10 level IV
ecoregians: the Northern limestone/Dolomite Valleys (67a), the Northern Shale Valleys (67b),
the Northern Sandstone Ridges (67c), the Northern Dissected'Ridges (67d), die'Anthracite (67e),
the Southern Limestone/Dolomite Valleys and Low Rolling Hills (671), 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 ecoregioas 67f, 67g, 67h,
and 67i occurs in a broad zone near die James River.
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Northern Limestone/Dolomite Valleys (67a)
Ecoregion 67a is a lowland characterized by broad, level to undulating, fertile valleys that
are extensively fanned. The Great Valley, the Shenandoah Valley, and the Nittanp Valley all
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 (15-152 m).
Silurian, Ordovidan, and Cambrian limestone and dolomite commonly underlie ecoregion
67a. Interbedded with the carbonates are other rocks, including 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
latitudinal range. The growing season varies from 145 to 180 days and is sufficient for
agriculture. Farming predominates, with scattered woodlands occurring in steeper areas. 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.
Figure 1 shows the boundaries of the Northern Limestone/Dolomite Valleys (67a); base*
rich soil, muted terrain, 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. It is 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-
152 m).
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, die stream turbidity can be comparatively high and the stream habitat relatively
impaired.
Inceptisols (Dystrochrepts) have developed from residuum, and Berks, Weikert, and
Lehew sotts 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, fanning
predominates, with woodland occurring on steeper sites. Scattered shale barrens occur on steep
26
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west end south facing slopes; it is one of rarest types of habitat in Pennsylvania and occurs in
Huntingdon, Fulton, and Bedford counties (Cuff and others, 1989, p. 56; Erdman and Wiegman,
1974, pp. 71-74).
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 in
ecoregion 67c or in the Southern Sandstone Ridges (67h). High-gradient streams flow off the
ridges into narrow valleys. Streams do not have as much buffering capacity as ecoregion 67d or
67i and are subject to acidification. The ridge-forming 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 significantly 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.
Kuchler (1964) mapped the natural vegetation as mostly Appalachian oak forest in the
north and oak/hickoiy/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 (61-351 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, Lode Haven, Chemung, and
Trimmers Rode Formations and, in Maryland, the Chemung Group. They are Devonian in age
and folded. The soils developed from this interbedded rode 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 ecaregion, but
there are also some pastures. Shale barrens occur on steep west and south facing slopes, they
consist of stunted trees [including eastern red cedar (Juniperus virginiana), Virginia pine (Pinus
27
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virgmjana), and chestnut oak (Quercus prims)J, thickets of shrubs [including hawthorn
(Crataegus vniflora), Allegheny plum (Prunus alieghaniensis), huckleberry (GayJussacia
baecata)], and herbaceous vegetation [including mountain parsley (Taenhtia montana), moss pink
(Phlox subulata), barrens ragwort (Semdo antermariifolius), birdfoot violet {Viola pedata) and
Kate's mountain clover (Trifolium virginicum) (Cuff and others, 1989, p. 56; Erdman and
Wiegman, 1974, pp. 71-74). 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 ridges, knobs, and minor
valleys of ecoregion 67d. They are morphologically distinct from the sharp ridges 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. Landfonns, 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 (Dystrochiepts), and Ultisols (Fragiudults).
The natural forest was Appalachian oak forest with some northern hardwood forest.
Today cheny 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 characterized 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 gende 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 underlie 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. Fanning 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
Rolling Hills (67f); 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 whiJe 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 tine grained rock Local relief varies from about
125 feet to 650 feet (38-198 m). The terrain is often more rugged than that of ecoregion 67b.
Woodland occurs on steeper sites and fanning is common elsewhere.
The Brallier, Rome, Elbrook, Chemung, and Clinton Formations commonly underlie
ecoregion 67g They are folded and fad ted, and are of Paleozoic age. The underlying rock is aot
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 67g than in the Southern
Limestone/ Dolomite Valleys and Low Rolling Hills (67f); stream turbidity can, therefore, be
comparatively high and the riverine 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 aldose acidic to
neutral valley and low hill soils that developed primarily on interbedded shales and siltstones.
To the north, in ecoregion 67b, grew oak/hickory/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 67h. 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 (Fragjudults) 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
671 and 67c. To the north grew oafcftickory/pine forest and to the south, in ecoregion 67h, grew
Appalachian oak forest. Today, extensive forest covers ecoregjon 67h
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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 characteristic of the
ecoregion and were distinct from the oak/hickoiy/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 intabedded sedimentary rocks including siltstones. Crestal elevation ranges from
approximately 2,100 feet to 4,ISO feet (640-1,265 m), and local relief varies from about ISO 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 Devonian age sedimentary rocks; the
Chemung Group and the Brallier Formation are common. The soils developed from this
inteibedded rock are mostly Inceptisols (Dystrochrepts) and Ultisols (Fragiudults); Berks,
Lai dig, 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 distinct 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. It is a high, dissected, and nigged 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 SO feet (IS m) in mountain glades to over 1,9S0 feet (S94 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 nigged
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 1; Heriihy 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 ecoregjons: die Forested Hits and Mountains (69a), die Uplands and Valleys of Mixed Land
Use (69b), the Greenbrier 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 nigged parts of ecoregian 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)i
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
en 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 (Neotomajloridana), found on tie cliff faces and
boulder piles of watergaps, 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 buffering capacity and many readies, including some not affected by mine
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 (96-1S2 cm), while the
average growing season is only 135-155 days (U.S. Department of Agriculture, 1972). The high,
nigged topography has a heavy impact on the climate. The average annual temperatures of
ecoregian 69a can be more than 10°F (5°C) lower and die 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
(Dystrochrepts, Fragiochrepts, Haplaquepts) that are acidic, steep, often stony, and low in
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nutrients. The relatively infertile soils, cod climate, short growing season, and ruggedness of
ecoregion 69a make the area particularly unsuited to agriculture. The original 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 rubens) and hemlock (Tsuga canadensis) (Williams and
Fridley, 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 Cranberry Glades northwest of Hillsboro, West
Virginia, occur in highland bowls that trap cold air and have restricted water drainage; sphagnum
moss, black spruce (Picea mariana), and tamarack {Larix laricina) grow hoe (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 Christmas 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 underlain 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, Pennsylvania. Bituminous coal
mines are numerous. The rounded hills and low ridges attain elevations of 1,375-2,800 feet (419-
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).
Pennsylvanian 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 {Larix laricina) also occurred. Isolated
remnants of the original vegetation can still be found and Markelysburg Bog, near Faimington,
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Pennsylvania, is the type locality of the Allegheny glade gentian {Gentian saponaris var
AJlegheniensis) (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 fanning 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 occuned (Biesecker and George, 1966, Plate 1; Dyer,
1982b; Herlihy and others 1990, Table IV)
The boundary between ecoregions 69b and 70c is determined primarily 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 ecoregjons 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 drainage feeds the Greenbrier River, which has large amounts of year around, high-
quality flow. Crestal elevations range from about 1,800 to 2,900 feet (549-884 m). Lower areas
have an adequate growing season (up to 165 days) for pasture, small grain, and com (Gorman,
1972). Valley bottoms are typically ISO 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 Bluefield and Maccrady Formations, and
are composed primarily of limestone and shale. Deep, gently sloping and well-drained 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 in adjacent ecoregions (Raitz and others, 1984, 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 (Hi the limestone soils of
steeper slopes (Williams and Fridley, 1938). Elsewhere, such as on the Big Levels and the Litde
Levels, bluegrass pasture and hay crops predominate. These permanent pastures have remained
excellent since they were cleared in die late-18th century and support beef cattle, sheep, poultry,
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and daily farming. The Greenbrier Karst (69c) is among West Virginia's principal livestock
producing areas (Raitz and others, 1984, p. 70).
The ecoregion boundary follows the break in topography, geology, land use, natural
vegetation, and soil; karst topography, limestone bedrock, permanent pastures, original
oak/hickory forest, and fertile, high base soils are characteristic 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 primarily underlain by flat-lying Pennsylvanian
sandstone, siltstone, shale, and coal of the Pottsville 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 Ciolkosz, 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, 1982b;
Herlihy and others, 1990, Table IV; Kinney, 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 nigged 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-suburb an-industrial activity, general
farms, pastures, forests, coal mines, and oil-gas fields. Urban and industrial land use
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predominates along the major rivers, especially in the Pittsburgh area. Elsewhere, agricultural
land is common except in rugged areas where forests are dominant Bituminous coal mining is
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 industrial operations diminished 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/Ontario Hills and Lake Plain (61) approximates the
Wisconsinan 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 Pennsylvanian 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 sedimentaiy rock,
and mined for coal. Descriptions of the individual characteristics of these three ecoregions
follow.
Permian Hills (70a)
Hie Permian 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. Hie
terrain becomes more rugged toward the southwest, as the rounded hills and shallow valleys
gradually dose 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 derived 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 com and hay forming 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 ga$ production occur in ecoregion 70a.
inhabiting ecoregion 70a is at least one species that is endangered, the small-whoried
pogonia (Isotria medeoloides). This woodland orchid was the first Pennsylvania species listed
by the federal government as endangered (Wiegman, 1985, p. 49).
The boundary between ecoregion 70a and die Monongahela Transition Zone (70b)
generally follows the gedogic division between the Washington and Waynesboro Formations.
35
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The Penman 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
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, ungladated 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 AJfisols 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 river valleys that also serve as transportation corridors. Bituminous coal mining is
common and some oil production occurs. There is also some general fanning and woodland, but
these are less prevalent than in ecoregion 70c.
Acid mine drainage, siltation, and industrial pollution have degraded stream habitat in
ecoregion 70b affecting fish and invertebrates. As a result, the eastern sand darter (.Ammocrypta
pettucida) was extirpated from the Ohio River drainage of Pennsylvania (Cooper, 1983, p. 189)
and the obscure clubtail dragonfly (Progomphus 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, including the smallmouth 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 noncaibonate Conemaugh Group.
This line conforms to where the soils of ecoregion 70c meet the base-saturated AJfisols of
ecoregion 70b (Cunningham and Ciolkosz, 1984). The boundary between ecoregions 70b and 70a
conforms to the junction between the Permian Washington 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, gendy dipping strata, general
farming, land slides, and bituminous coal mining. The terrain of ecoregion 70c has a maximum
36
-------
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
from 1,200 to 1,300 feet (366-396 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 tmd 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, Hazleton, Weikert, Cavode, and Rayne soils are
common and are derived primarily 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 mining. Different soil occur outside of ecoregion
70c which has more Gilpin soils than ecoregion 62d and fewer Alfisols than in the Monongahela
Transition Zone (70b) 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 daiiy 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 base-poor 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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2
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Conestoga Formation, afso Ordovidan
dolomite and shale and Cambrian carbonates.
jftooos rode. VA.: basalt, indabesah of the
Catoctm FoRnatton; granite and eranodiorite
of die Virginia Btne Ridge Complex;
tndeaite, tufl and greenstone of tne Swift Rim
Formation. PA.: meUihyoUts-meiahanlt.
Mostly Hattaddb; also Kaptodnlta, Eotrochrepts
' Mestc / Duffidd, Hagerstown, Letort. Petpea.
^onestoga, Betfington
?ubocBep^fC^OP K5u3ii3uite;13s7—
-laphidults / Mcsic t Catocttn, Myersville.
¦IsyesvUle, ArendtsviDe / Low Fertility, acidity,
ton nets, steepness
170-190
<0-3?rtiiCTe3JJ'
loofliwardy 150-
175; less Brest
frequency in
TooUttUs.
Mostly ApcdacMan oak foresL
Sonw odE/nickoryfkibM fond
ilong Susquehanna River.
^pSeEn AToreit ™
Extensive general, com, hay,
dairy, livestock, tobacco
branny. Reddentid area
increarmg.
Extensive forest cover.
Locdized dairving, poidtry
rassirv, orchards are foml on
the Areixbville soils.
SdEaaErTod
IW».
vSSmSTai
Jagladated MA steeply
fadni riifeea, rap-narrow
r«Qey*.
1,300 to
>3,500: Idghed
n wrack i
naoc. 1,000
Cambrian sedimentary, metsseiiiTPcntary
rock of (he Wererton-Loadon, Antietam,
Hvperm Formations (Eiwin, Hampton
reepeetitdy in Virginia)
Jystrochiepd; alao FragnxkJts, Haptoddta, and
4aphad«tCi t Mestc / Lddg, Wallen, DekdK
^ily, Boka, Weikcrt; Cdgnnont, Highfidd I
Stflnnesak steepness, acubty, low fertility
40-49; mneasing
to tooth t
150-175; less frod
tn footfault.
Appal arfaaa oak fbrest
Extensivdy forested
Ratemm**
1.113
JngJadated. Hilly btgb pfsTrin.
tottered nwnitmwfct. New River
lot indeed.
!^oo-4^oo r
jften under 200
Piecambnan wetamoiptuc rock, mchiding
quaitate, graywacke, conglomente of the
Lynchburg Formation. Also gneiss, eddst,
Rartzite.
^rstrocfarepts, Hadnddb, dso Ultisds / Mesic /
Chester, Hayerrille, Qlenelg. Manor, Myersville
Stoninesa, shtDosmess
About £4/
175
^tyarathian oak lOrest,
»k/hic)nry^pine forest
Often wooded. Some dairy-
hvestoek pastures and apple
orcharda.
M&m {pseaa
¦Maw mi
III III f«M>
/
1M
Jngtadated. Hj|hii4M
Tiuuirtiiflt; wd dissected itap
tape*.
L,600-5.721 on
tft Regta/
Tftan 1.150-
1.500
'¦icoeoic iTiyofate porphyry, arkose, tufi, ML
Rogers Votcanie Otonp; Precanibrtan Virginia
Bhie Ridge Cormim; pbyllite, omtiate,
graywacke, cowgwoente: Lynctibarg
roimttiop-
Jystiothiepta. Kaplndolts / Mestc / Hayesville,
3rimsley, ratoi / Stoninesa, deepness
Abort 41/
160-170
Appdadrian oak teed and
Kme nuthein Uaidwuud Cored
il high derations.
Extemve forest cover.
¦®-
tlMW
MMTdVI
ffl.'
UtaghdafeBd UA steep rid(es;
loep, nation raUey*.
oxupHn east
Lerd to cwM«tin nibyi,
tuttewd low ridge*, karst
cmlii
i.«S44-4.4U 1
VO-l.iX
tSSCSQ
aotmn/
$0*300
Cainbrian sednnentary and metaseitmentMy
reek. Smttan^witate farm crest*-, state,
phjrlBte, ailtstane, sandstone form side slopes.
fc5omuun5y"ToTfcrand^aolt^ STrnTsnT-
Ordovican, and Cambrian Hmestone,
Uonite, and calcareous ahsle.
tfodhr Dntrochrepts / Medc / Berks, Weikert
Jekatk iraUm
4ap|odtiIts, Pdeoodts 7 Mesic 7 Hsgerstown
ton mm tocdly
AW J!/
160-17D
U7
145-180
Appdaebian oak bred and
**» northern hardwood fcrest
it feigfa deration
IGfly TppBBnm^TflrS "
n north and oak/hi ^ory/ftne
rorest ia south.
Externvdy forested.
on steep dtes. Loed
uroonrsoBaroan oeveiopnieni.
HmKuBJi
v,w
(JnaJadatad cconM imBmh!
lolling *dteya, fritted USft.
VtrisHe/
SO-ffO
PbUed'CBDlted Devedan shahts, siltatanea,
nd fine gmned mulHuues of (be Hansttoo,
Haimwtiiie, Brattier, Chenrang Fermatiom,
and Chnnm Qrotn Some calcareous areas
Mosdy Dystrochrepta/ Mesk / Bob, Wctkcd
130-ISO
Mostly Appdadnn oak bred
iot oafcABaoryfcta* fenst to
mjuOl
Farnam. othan, or subcrtwa
oaes. Wooded where steep «r
poovty drained.
»¦¦¦¦
C3.'
opqpi ^ imfiiwrt
"—'H whip iaigia» mv*
nllqn.
ISiS?"
~istoa Group and Tusuuui. Poccim, Bald
E«g|e Fmmtlicsu mmiMii Pileeaoki
landatDoa and "wgTiwnm^ fljini cruk,
•wkeiroek onsloces.
Dyvtrorteepts, Fragraddts / Meaio f [Math,
«d>^ Berks, Wakert, Lehew / Steepness,
96-50 /
IIO-ISO
Mostly Appahdin oak bred
n norlh, oafc/Uckciy/ptae taad
n sooth
Forested.
jy|l»
"cSSmStT
kaH\ Weikert, Lddig / Strums, ihiilirti
U-Ut
170-175
Mostly Appalachian oak forest
FgrataL
SrShSt''
1*5
i/ninSM. rosea, ossociBa,
- ¦ ¦ » UJh - - » f \
man pibbi m irbbi
2e«dded eeetoea. VaOtyt
Z.100-4,150 /
150400
Mostly Devonian, some CMovtetan,
Lmnn uueiuennro weBiDHnny nm
ndoding cOtrtonea. Chiiiuuig, BiaQkr
Sysfroelnvpts, Fragiodolts / Mesio / Wakert,
Serks, Lddig, Wallen
U'Hf
170-175
Mostly Appalachian ode forest
Modly bnM Sane pastures
an wider floodptdns.
-------
Figure 1: Level III and IV Ecoregions of Pennsylvania and the Blue Ridge
Mountains, Ridge and Valley, and Central Appalachians of EPA Region 3
Low
60 NORTHERN APPALACHIAN PLATEAU
CI] 60a Glaciated Low Plateau
I I 60b Northeastern Uplands
61 ERIE/ONTARIO HILLS AND LAKE PLAIN
~ 61a Erie Lake Plain
Oil 61 b Mosquito Creek-Pymatuning Lowlands
I I 61 c Low Lime Till Plain
~
70 WESTERN ALLEGHENY PLATEAU
! ) 70a Permian Hills
I I 70b Monongahela Transition Zone
I I 70c Pittsburgh Low Plateau
58 NORTHEASTERN HIGHLANDS
58h Reading Prong
6 2 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
63a Delaware River Terraces and Uplands
64 NORTHERN PIEDMONT
64a Triassic Lowlands
64b Diabase and Conglomerate Uplands
64c Piedmont Uplands
64d Piedmont Limestone/Dolomite Lowlands
65 SOUTHEASTERN PLAINS
66 BLUE RIDGE MOUNTAINS
66a Northern Igneous Ridges
66b Northern Sedimentary-
Metasedimentary Ridges
66c Interior Plateau
66d Southern Igneous Ridges
and Mountains
66e Southern Sedimentary
Ridges J
Level III Boundary
Level IV Boundary
Stale Boundary
County Boundary
CD
n
~
LZj
~
~
~
r~i
B3
E3
~
67 RIDGE AND VALLEY
67a Northern Limestone/Dolomite Valley
67b Northern Shale Valleys
67c Northern Sandstone Ridges
67d Northern Dissected Ridges
67e Anthracite
671 Southern Limestone/Dolomite Valleys and
Rolling Hills
67g Southern Shale Valleys
67h Southern Sandstone Ridges
67i Southern Dissected Ridges and Knobs
69 CENTRAL APPALACHIANS
69a Forested Hills and Mountains
69b Uplands and Valleys of Mixed Land Use
69c Greenbrier Karst
69d Cumberland Mountains
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