﻿THE 
  GEOLOGICAL 
  HISTORY 
  OF 
  NEW 
  YORK 
  STATE 
  

  

  43 
  

  

  region 
  such 
  low 
  knobs 
  were 
  not 
  covered 
  by 
  the 
  water. 
  At 
  this 
  

   same 
  locality 
  there 
  is 
  a 
  fine 
  exhibition 
  of 
  coarse 
  conglomerate 
  

   at 
  the 
  base 
  of 
  the 
  Potsdam 
  sandstone, 
  the 
  boulders 
  of 
  the 
  con- 
  

   glomerate 
  often 
  ranging 
  from 
  one 
  to 
  three 
  feet 
  across. 
  These 
  

   boulders 
  were 
  torn 
  off 
  the 
  Adirondack 
  cliffs 
  by 
  the 
  waves 
  of 
  the 
  

   Potsdam 
  sea 
  and 
  were 
  deposited 
  near 
  shore 
  in 
  local 
  depressions 
  of 
  

   the 
  old 
  rock 
  surface. 
  The 
  sandstone 
  itself 
  everywhere 
  abounds 
  in 
  

   ripple 
  marks, 
  thus 
  proving 
  the 
  shallow 
  water 
  (near 
  shore) 
  origin 
  

   of 
  the 
  rock. 
  All 
  the 
  rock 
  in 
  the 
  walls 
  of 
  the 
  famous 
  Ausable 
  Chasm 
  

   (Clinton 
  county) 
  is 
  Potsdam 
  sandstone 
  (plate 
  18). 
  . 
  

  

  Immediately 
  overlying 
  the 
  Potsdam 
  and 
  showing 
  about 
  the 
  same 
  

   areal 
  distribution, 
  are 
  alternating 
  sandstones 
  and 
  limestone 
  beds 
  

   (Theresa 
  formation) 
  which 
  show 
  a 
  thickness 
  of 
  from 
  50 
  to 
  200 
  

   feet. 
  After 
  still 
  greater 
  subsidence, 
  the 
  important 
  formation 
  known 
  

   as 
  the 
  Little 
  Falls 
  dolomite 
  (limestone) 
  was 
  deposited, 
  layer 
  upon 
  

  

  Fig. 
  15 
  Section 
  passing 
  through 
  North 
  Galway 
  in 
  Saratoga 
  co. 
  and 
  show- 
  

   ing 
  how 
  the 
  Cambric 
  (Potsdam 
  and 
  Theresa) 
  strata 
  overlap 
  upon 
  a 
  hillock 
  

   of 
  Precambric 
  rock. 
  This 
  knob 
  of 
  Precambric 
  rock 
  stood 
  above 
  the 
  general 
  

   level 
  of 
  the 
  peneplain 
  (early 
  Paleozoic) 
  and 
  was 
  not 
  submerged 
  under 
  the 
  

   Potsdam 
  sea. 
  

  

  After 
  W. 
  J. 
  Miller, 
  N. 
  Y. 
  State 
  Mus. 
  Bui 
  153, 
  p 
  5 
  

  

  layer, 
  in 
  the 
  Upper 
  Cambric 
  sea. 
  This 
  formation 
  which 
  is 
  hard, 
  

   compact 
  and 
  of 
  light 
  gray 
  color, 
  shows 
  a 
  thickness 
  of 
  several 
  hun- 
  

   dred 
  feet 
  in 
  the 
  gorge 
  at 
  Little 
  Falls. 
  It 
  rests 
  directly 
  upon 
  the 
  

   Precambric 
  rock 
  there 
  (see 
  figure 
  7), 
  which 
  shows 
  that 
  the 
  Cam- 
  

   bric 
  sea 
  spread 
  over 
  that 
  region 
  for 
  the 
  first 
  time 
  when 
  that 
  dolo- 
  

   mite 
  was 
  forming. 
  The 
  Little 
  Falls 
  sea 
  swept 
  all 
  around 
  the 
  Adi- 
  

   rondacks, 
  except 
  what 
  is 
  now 
  the 
  western 
  border 
  from 
  Trenton 
  

   Falls 
  to 
  the 
  Thousand 
  islands 
  district. 
  Occurrence 
  of 
  the 
  dolomite 
  

   in 
  small 
  outlying 
  masses 
  at 
  Wells 
  (Hamilton 
  county) 
  and 
  Schroon 
  

   Lake 
  (Essex 
  county) 
  proves 
  that 
  the 
  Little 
  Falls 
  sea 
  extended 
  well 
  

   into 
  the 
  eastern 
  Adirondacks. 
  Rocks 
  of 
  this 
  age 
  appear 
  to 
  be 
  pres- 
  

   ent 
  in 
  southeastern 
  New 
  York 
  and 
  if 
  so, 
  the 
  Little 
  Falls 
  sea 
  also 
  

   overspread 
  that 
  region. 
  Direct 
  evidence 
  for 
  western 
  and 
  southern 
  

  

  