﻿SEPT. 
  19, 
  1922 
  STOSE 
  AND 
  JONAS: 
  LOWER 
  PALEOZOIC 
  OF 
  PENNSYLVANIA 
  365 
  

  

  thickness 
  is 
  not 
  known, 
  but 
  it 
  is 
  probably 
  several 
  hundred 
  feet. 
  The 
  

   marble 
  conglomerates 
  that 
  occur 
  at 
  or 
  near 
  the 
  base 
  were 
  described 
  

   by 
  Walcott'^ 
  as 
  intraformational 
  conglomerates 
  in 
  the 
  Lower 
  Cambrian 
  

   sediments. 
  At 
  the 
  Bellemont 
  quarries, 
  12 
  miles 
  southeast 
  of 
  Lan- 
  

   caster, 
  one 
  of 
  the 
  many 
  excellent 
  exposures, 
  the 
  conglomerates 
  occur 
  

   at 
  about 
  the 
  horizon 
  of 
  the 
  banded 
  dark 
  blue 
  argillaceous 
  limestone 
  

   and 
  knotty 
  white-marble 
  pseudo-conglomerate 
  beds 
  of 
  the 
  Kinzers 
  

   formation, 
  and 
  at 
  first 
  were 
  regarded 
  by 
  the 
  writers 
  as 
  an 
  expansion 
  

   of 
  this 
  formation. 
  Later 
  work 
  in 
  other 
  parts 
  of 
  the 
  region 
  has 
  shown 
  

   that 
  the 
  Conestoga 
  limestone 
  is 
  an 
  overlapping 
  and 
  much 
  younger 
  

   formation. 
  In 
  the 
  northeastern 
  outskirts 
  of 
  Lancaster, 
  the 
  coarse 
  

   basal 
  limestone 
  conglomerate 
  clearly 
  fills 
  depressions 
  in 
  the 
  upper 
  

   surface 
  of 
  the 
  Ledger 
  dolomite. 
  North 
  of 
  Vintage, 
  it 
  overlaps 
  on 
  

   the 
  Kinzers 
  formation. 
  At 
  the 
  Bellemont 
  quarries 
  it 
  lies 
  on 
  the 
  Vin- 
  

   tage 
  dolomite. 
  Five 
  miles 
  south 
  of 
  Vintage 
  it 
  overlaps 
  on 
  the 
  Harpers 
  

   schist. 
  The 
  basal 
  beds 
  of 
  the 
  Conestoga 
  are 
  so 
  variable 
  that 
  no 
  

   consecutive 
  section 
  has 
  been 
  recognized 
  for 
  any 
  distance, 
  a 
  fact 
  that 
  

   made 
  it 
  very 
  difficult 
  to 
  distinguish 
  the 
  formation 
  from 
  the 
  limestone 
  

   on 
  which 
  it 
  rests 
  and 
  to 
  draw 
  its 
  boundary 
  with 
  certainty 
  at 
  many 
  

   places. 
  The 
  characters 
  of 
  the 
  basal 
  beds 
  of 
  the 
  Conestoga 
  vary 
  

   with 
  the 
  formation 
  on 
  which 
  they 
  overlap 
  and 
  from 
  which 
  they 
  were 
  

   largely 
  derived. 
  

  

  West 
  and 
  north 
  of 
  Welsh 
  Mountain 
  the 
  section 
  is 
  continuous 
  from 
  

   the 
  Vintage 
  dolomite 
  up 
  to 
  the 
  Beekmantown 
  limestone 
  with 
  no 
  indi- 
  

   <:ation 
  of 
  Conestoga 
  type 
  of 
  sedimentation, 
  and 
  as 
  the 
  Conestoga 
  is 
  

   known 
  to 
  unconformably 
  overlie 
  the 
  Ledger, 
  it 
  is 
  believed 
  to 
  be 
  younger 
  

   than 
  the 
  Beekmantown. 
  A 
  few 
  brachiopods 
  and 
  crinoid 
  plates 
  and 
  

   stems 
  recently 
  found 
  by 
  the 
  writers 
  in 
  the 
  lower 
  beds 
  of 
  the 
  Cone- 
  

   stoga 
  limestone 
  east 
  of 
  York, 
  Pa. 
  , 
  have 
  been 
  identified 
  by 
  Ulrich 
  as 
  forms 
  

   found 
  in 
  the 
  Frederick 
  limestone 
  of 
  Frederick 
  Valley 
  which 
  is 
  probably 
  

   of 
  Chazy 
  age. 
  The 
  Frederick 
  limestone 
  also 
  somewhat 
  resembles 
  

   the 
  Conestoga 
  limestone 
  in 
  appearance 
  and 
  they 
  are 
  probably 
  in 
  part 
  

   equivalent, 
  but 
  the 
  greater 
  thickness 
  and 
  extent 
  of 
  the 
  lime-stones 
  

   to 
  which 
  the 
  name 
  Conestoga 
  is 
  applied 
  are 
  believed 
  to 
  warrant 
  a 
  sep- 
  

   arate 
  formation 
  name. 
  The 
  Frederick 
  limestone 
  rests 
  on 
  Beekman- 
  

   town 
  limestone 
  in 
  Frederick 
  Valley 
  and 
  the 
  Cocalico 
  shale 
  rests 
  on 
  

   the 
  Beekmantown 
  northeast 
  of 
  Lancaster. 
  The 
  Conestoga 
  limestone, 
  

   which 
  is 
  an 
  argillaceous 
  limestone 
  with 
  many 
  shaly 
  beds, 
  may 
  therefore 
  

   be 
  in 
  part 
  the 
  southeastward 
  representative 
  of 
  part 
  of 
  the 
  Cocalico 
  shale. 
  

  

  3 
  C. 
  D. 
  Walcott. 
  U. 
  S. 
  Geol. 
  Survey, 
  Bull. 
  134: 
  17-19. 
  1896. 
  

  

  