﻿GEOLOGY 
  OF 
  THOUSAND 
  ISLANDS 
  REGION 
  73 
  

  

  8' 
  Gray 
  magnesian 
  limestone, 
  weathering 
  whitish, 
  fairly 
  massive 
  be- 
  

  

  low, 
  upper 
  2 
  to 
  3 
  feet 
  thin 
  bedded 
  and 
  earthy 
  

  

  i' 
  6" 
  Curdled 
  looking 
  intergrowth 
  of 
  blue 
  limestone 
  and 
  gray, 
  mag- 
  

   nesian 
  limestone, 
  the 
  former 
  weathering 
  most 
  rapidly 
  with 
  pro- 
  

   duction 
  of 
  fantastic 
  weathered 
  surface 
  

   19' 
  Alternating, 
  gray, 
  earthy, 
  impure 
  magnesian 
  limestones, 
  and 
  thin, 
  

  

  shaly 
  looking 
  partings, 
  limestone 
  weathering 
  at 
  times 
  to 
  a 
  green- 
  

   ish 
  tinge, 
  at 
  other 
  times 
  whitish 
  

  

  2' 
  Greenish 
  to 
  olive, 
  calcareous 
  shale 
  

  

  2' 
  Greenish, 
  calcareous 
  sandstone, 
  coarse, 
  well 
  rounded 
  sand 
  grains 
  

  

  set 
  in 
  calcite 
  paste 
  

  

  72' 
  y2 
  

  

  The 
  lower 
  4 
  feet 
  of 
  the 
  section 
  belong 
  with 
  the 
  basal, 
  sandy 
  por- 
  

   tion 
  of 
  the 
  formation, 
  without 
  any 
  question, 
  so 
  that 
  the 
  actual 
  

   base 
  is 
  nearly 
  reached. 
  Above 
  is 
  a 
  thickness 
  of 
  28 
  feet 
  of 
  im- 
  

   pure, 
  magnesian 
  limestone 
  before 
  reaching 
  the 
  base 
  of 
  the 
  fos- 
  

   siliferous 
  black 
  limestone, 
  the 
  most 
  characteristic 
  member 
  of 
  the 
  

   lower 
  division. 
  Plate 
  16 
  is 
  a 
  photograph 
  of 
  beds 
  of 
  this 
  hori- 
  

   zon 
  exposed 
  in 
  the 
  creek 
  bed 
  just 
  north 
  of 
  the 
  road 
  i^ 
  miles 
  east 
  

   of 
  Perch 
  lake. 
  In 
  the 
  section 
  here 
  14 
  feet 
  only 
  of 
  gray 
  magnesian 
  

   beds 
  are 
  found 
  underneath 
  the 
  black 
  limestone, 
  as 
  against 
  the 
  28 
  

   feet 
  of 
  the 
  Perch 
  lake 
  section. 
  A 
  mile 
  further 
  east 
  these 
  have 
  dis- 
  

   appeared 
  letting 
  the 
  black 
  limestone 
  down 
  on 
  the 
  basal 
  sand 
  beds, 
  or 
  

   rather 
  bringing 
  them 
  up 
  to 
  it. 
  

  

  Judging 
  from 
  other 
  sections 
  the 
  concealed 
  10 
  feet 
  of 
  the 
  section 
  

   is 
  occupied 
  by 
  weak, 
  earthy, 
  thin 
  bedded, 
  whitish 
  limestone, 
  and 
  

   the 
  section 
  would 
  be 
  capped 
  by 
  a 
  very 
  massive, 
  blue, 
  subcrystalline 
  

   limestone 
  which 
  forms 
  a 
  strong 
  shelf 
  'everywhere 
  through 
  the 
  

   district. 
  

  

  The 
  best 
  sections 
  of 
  the 
  upper 
  division 
  are 
  all 
  on 
  the 
  Clayton 
  

   quadrangle. 
  One 
  measured 
  up 
  the 
  bed 
  of 
  the 
  small 
  creek 
  which 
  

   tumbles 
  down 
  the 
  blui¥ 
  into 
  the 
  Chaumont 
  river 
  a 
  mile 
  southwest 
  of 
  

   Depauville 
  is 
  as 
  follows 
  : 
  

  

  i' 
  8'' 
  Brittle, 
  light 
  gray, 
  subcrystalline 
  limestone 
  

  

  16' 
  i" 
  Thin 
  bedded, 
  brittle 
  limestone, 
  mostly 
  dove, 
  but 
  with 
  beds 
  of 
  

   grayer 
  limestone 
  

  

  \' 
  IMassive 
  layer 
  of 
  dove 
  limestone 
  

  

  10' 
  8" 
  Irregularly 
  bedded, 
  gray 
  to 
  white, 
  earthy 
  limestone, 
  mostly 
  thick 
  

   bedded 
  ; 
  midway 
  is 
  somewhat 
  sandy 
  

  

  5' 
  Thick 
  bedded, 
  uneven, 
  gray 
  limestone 
  

  

  3' 
  Thin 
  bedded 
  dove 
  limestone 
  in 
  3" 
  to 
  6" 
  layers 
  

  

  4' 
  2" 
  Gray 
  white, 
  earthy, 
  irregular 
  limestone, 
  both 
  thick 
  and 
  thin 
  beds 
  

  

  5' 
  4" 
  Dark 
  and 
  light 
  gray, 
  brittle, 
  subcrystalline 
  limestone 
  

  

  i' 
  8" 
  Gray 
  white, 
  impure, 
  earthy 
  limestone 
  

  

  V 
  8" 
  Brittle, 
  blue 
  gray, 
  suborranular 
  limestone 
  

  

  5' 
  10" 
  Impure, 
  earthy, 
  white 
  limestone, 
  irregularly 
  bedded 
  

  

  i' 
  Hard, 
  blue 
  gray, 
  subcrystalline 
  limestone 
  

  

  5/ 
  I" 
  

  

  