galerie; (German.) Gallerie, Stollen;
  (Greek.) ypohios thiothos; (Italian.)
  cunicolo, gatteria; (Russian.) hod;
  (Spanish.) galeria; (Turkish.) geqit;
  (Yugoslavian.) galerija.  See also
  chamber; room.

pathogenic bacteria.  Disease inducing
  bacteria[16].

pavement. See limestone pavement.

peat. Decomposed matter, mainly
  vegetable1161.

pebble. A smooth rounded rock
  fragment1163.

Peclet number.  1. measure of the relative
   contribution of mechanical dispersion and
   diffusion to solute transport. It relates the
   effectiveness of mass transport by
   advection (-ff=-*f)  to the
   effectiveness of mass transport by either
   dispersion or diffusion \P. = 4^J.  Peclet

   numbers below =0.4 indicate
   diffusion/dispersion control; 0.4-6.0
   suggest that diffusion/dispersion and
   advectiori are in transition and thus
   approximately equal to each other; and
   >6.0 indicate advection  control.  Large
   Peclet numbers indicate strongly
   advective systems.  2. A relationship
   between the advective and diffusive
   components of solute transport expressed
   as the ratio of the product of the average
   interstitial velocity, times the
   characteristic  length, divided by the
   coefficient of molecular diffusion. Small
   values indicate diffusion dominance,
   large values indicate advection
   dominance1221.
pearl. See cave pearl.

pediment. An inclined erosion surface
  covered with thin fluvial deposits1161.

pendulite. A kind of stalactite which has
  been partly submerged1253.

and the submerged part covered with
dog-tooth spar to give the appearance of a
drumstick.

pellicular water.  1. The film of water left
   around each grain or fracture surface of
   water-bearing material after gravity
   drainage1223.  2. Water of-adhesion[22].  3.
   Water that can be extracted by root
   absorption and evaporation but cannot be
   moved by gravity or by the unbalanced
   film forces resulting from localized
   evaporation and transpiration1221.

peloid. A microscopic texture. A
   sedimentary grain composed of micrite
   carbonate irrespective of origin[20].
   Synonyms: (French.) pelo'ide; (German.)
   mikroskopisches,  sedimentares Geftige;
   (Greek.) piloidis; (Italian.) peloide;
   (Spanish.) peloide; (Turkish.) peloit.
   See micrite, pelsparite.

 pelsparite.  A microscopic texture.  A  ,
   limestone composed of pellets (peloids)
   in a matrix of cement[20]. Synonyms:
   (French.) pelsparite; (German.)
   Pelsarite, Kalkstein gefiigt aus
   Kugelchen ?; (Greek.) pelsparitis;
   (Italian.) pelsparite; (Spanish.)
   pelsparita; (Turkish.) pelsparit.  See
   peloids.

 pendant, rock pendant. One of a group of
   isolated similarly proportioned
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