﻿34 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  POTSDAM 
  SANDSTONE 
  

  

  After 
  an 
  enormously 
  long 
  period 
  of 
  existence 
  as 
  a 
  land 
  area, 
  

   whose 
  duration 
  comprised 
  all 
  the 
  latter 
  portion 
  of 
  Precambric 
  

   time 
  and 
  most 
  of 
  the 
  Cambric 
  as 
  well, 
  and 
  whose 
  history 
  is 
  re- 
  

   corded 
  in 
  erosion 
  of 
  the 
  Precambric 
  rocks, 
  the 
  eastern 
  margin 
  of 
  

   the 
  Adirondacks 
  became 
  depressed 
  and 
  deposits 
  commenced 
  to 
  ac- 
  

   cumulate 
  upon 
  its 
  surface. 
  Thus 
  began 
  the 
  formation 
  of 
  the 
  

   Potsdam 
  sandstone. 
  

  

  The 
  deposit 
  began 
  on 
  the 
  northeast 
  and 
  extended 
  both 
  west 
  and 
  

   south, 
  accumulating 
  in 
  sinking 
  troughs 
  along 
  the 
  line 
  of 
  the 
  Cham- 
  

   plain 
  and 
  St 
  Lawrence 
  valleys. 
  It 
  is 
  thickest 
  in 
  Clinton 
  county, 
  

   where 
  the 
  thickness 
  is 
  an 
  unknown 
  amount 
  in 
  excess 
  of 
  iooo 
  feet 
  

   and 
  where 
  the 
  lower 
  beds 
  are 
  unlike 
  those 
  shown 
  elsewhere. 
  These 
  

   beds 
  are 
  coarse 
  conglomerates, 
  feldspathic 
  sandstones 
  and 
  ferru- 
  

   ginous, 
  shaly 
  sandstones, 
  wholly 
  without 
  fossils 
  and 
  apparently 
  de- 
  

   posited 
  above 
  sea 
  level. 
  They 
  are 
  followed 
  above 
  by 
  purer, 
  quartz 
  

   sandstones, 
  white, 
  gray, 
  yellow, 
  brown 
  or 
  red 
  in 
  color, 
  mostly 
  very 
  

   thoroughly 
  cemented 
  and 
  resistant 
  rocks. 
  Above 
  come 
  less 
  firm, 
  

   somewhat 
  calcareous 
  sandstones, 
  forming 
  the 
  upper 
  part 
  of 
  the 
  

   formation. 
  In 
  this 
  upper 
  division 
  and 
  in 
  the 
  upper 
  part 
  of 
  the 
  

   preceding 
  division 
  a 
  scant 
  fauna 
  appears 
  which 
  shows 
  that 
  this 
  

   portion 
  of 
  the 
  formation 
  is 
  marine. 
  

  

  It 
  is 
  only 
  this 
  upper 
  division 
  of 
  the 
  formation 
  which 
  is 
  found 
  in 
  

   Saratoga 
  county. 
  The 
  thickness 
  here 
  does 
  not 
  average 
  in 
  excess 
  

   of 
  100 
  feet, 
  ranging 
  from 
  50 
  to 
  150 
  feet, 
  the 
  variations 
  being 
  

   chiefly 
  due 
  to 
  the 
  irregularity 
  of 
  the 
  Precambric 
  surface 
  upon 
  

   which 
  it 
  was 
  deposited. 
  There 
  is 
  usually 
  found 
  a 
  few 
  feet 
  of 
  

   basal 
  conglomerate, 
  seldom 
  very 
  coarse, 
  above 
  which 
  the 
  formation 
  

   is 
  unbroken 
  sandstone, 
  the 
  lower 
  half 
  siliceous, 
  the 
  upper 
  cal- 
  

   careous, 
  in 
  which 
  many 
  of 
  the 
  beds 
  weather 
  to 
  an 
  ochreous 
  rotten 
  

   stone. 
  No 
  fossils 
  were 
  seen 
  by 
  us 
  in 
  the 
  formation 
  on 
  the 
  Sara- 
  

   toga 
  quadrangle, 
  though 
  Miller 
  found 
  L 
  i 
  n 
  g 
  u 
  1 
  e 
  p 
  i 
  s 
  acumi- 
  

   nata 
  in 
  it 
  on 
  the 
  adjacent 
  Broadalbin 
  quadrangle. 
  

  

  About 
  Saratoga 
  the 
  most 
  extensive 
  exposures 
  of 
  the 
  formation 
  

   are 
  those 
  north 
  of 
  the 
  village 
  in 
  Greenfield 
  township. 
  It 
  is 
  also 
  

   thinly 
  exposed 
  at 
  Corinth. 
  The 
  best 
  continuous 
  section 
  is 
  exposed 
  

   along 
  a 
  small 
  branch 
  of 
  Glowegee 
  creek, 
  a 
  mile 
  south 
  of 
  East 
  Gal- 
  

   way. 
  At 
  the 
  base 
  of. 
  the 
  section 
  the 
  creek 
  cuts 
  down 
  into 
  the 
  Pre- 
  

   cambric, 
  exposing 
  a 
  small 
  outlier 
  of 
  this 
  formation. 
  Above 
  this 
  a 
  

   continuous 
  section 
  200 
  feet 
  thick 
  is 
  exposed. 
  The 
  lower 
  50 
  feet 
  is 
  

   chiefly 
  sandstone, 
  with 
  occasional 
  beds 
  of 
  calcareous 
  sandstone 
  ; 
  in 
  

  

  