﻿GEOLOGIC 
  FORMATIONS 
  OF 
  NEW 
  YORK 
  147 
  

  

  a 
  total 
  thickness 
  of 
  200 
  or 
  300 
  feet. 
  It 
  is 
  well 
  seen 
  at 
  the 
  ^ 
  Noses 
  * 
  

   about 
  Fonda 
  on 
  the 
  Mohawk, 
  and 
  also 
  at 
  Littlefalls; 
  in 
  each 
  of 
  

   which 
  places 
  it 
  has 
  been 
  raised 
  to 
  the 
  surface 
  by 
  an 
  uplift 
  which 
  

   has 
  brought 
  it 
  from 
  its 
  original 
  position 
  below 
  the 
  Hudson 
  river 
  

   shales 
  which 
  are 
  common 
  in 
  this 
  region. 
  It 
  may 
  also 
  be 
  seen 
  

   near 
  Middleville 
  on 
  West 
  Canada 
  creek 
  (where 
  it 
  contains 
  in 
  its 
  

   cavities 
  many 
  beautiful 
  quartz 
  crystals), 
  and 
  in 
  many 
  places 
  in 
  

   the 
  vicinity 
  of 
  Lake 
  Champlain 
  and 
  the 
  St 
  Lawrence 
  river, 
  in 
  

   which 
  latter 
  region 
  it 
  has 
  some 
  layers 
  so 
  purely 
  calcareous 
  as 
  to 
  

   be 
  profitably 
  burnt 
  for 
  lime. 
  

  

  Outside 
  of 
  the 
  Mohawk 
  valley 
  the 
  Calciferous 
  is 
  a 
  true 
  lime- 
  

   stone 
  and 
  in 
  parts 
  of 
  Columbia, 
  Dutchess, 
  Putnam, 
  Westchester, 
  

   Orange 
  and 
  Rockland 
  counties 
  cannot 
  be 
  separated 
  from 
  the 
  

   Trenton. 
  

  

  Trenton 
  Group 
  

  

  Above 
  the 
  rocks 
  of 
  the 
  Calciferous 
  group 
  between 
  the 
  Mohawk 
  

   valley 
  and 
  the 
  Canadian 
  border 
  succeeds 
  a 
  thick 
  series 
  of 
  bedded 
  

   limestones 
  know^n 
  as 
  the 
  Trenton 
  group. 
  This 
  group 
  has 
  four 
  

   principal 
  divisions, 
  Chazy, 
  Birdseye, 
  Black 
  river 
  and 
  Trenton. 
  

   These 
  four 
  divisions 
  are 
  nowhere 
  all 
  found 
  together. 
  

  

  Chazy 
  Limestone 
  

  

  Overlying 
  the 
  Calciferous 
  sandrock 
  in 
  northern 
  New 
  York 
  is 
  a 
  

   dark, 
  irregular, 
  thick-bedded 
  limestone, 
  which 
  derives 
  its 
  name 
  

   from 
  the 
  village 
  in 
  Clinton 
  county 
  where 
  it 
  was 
  first 
  studied. 
  

  

  Its 
  thickness 
  is 
  about 
  730 
  feet 
  on 
  Lake 
  Champlain 
  : 
  but, 
  in 
  strik- 
  

   ing 
  contrast 
  with 
  the 
  wide 
  extent 
  of 
  many 
  other 
  rocks, 
  it 
  is 
  known 
  

   only 
  in 
  the 
  Champlain 
  valley, 
  and 
  does 
  not 
  appear 
  to 
  extend 
  in 
  

   any 
  considerable 
  thickness 
  into 
  those 
  parts 
  of 
  the 
  state 
  west 
  or 
  

   south 
  of 
  the 
  Adirondack 
  region. 
  It 
  is 
  not 
  seen 
  as 
  a 
  distinct 
  or 
  

   separate 
  mass 
  in 
  the 
  Mohawk 
  valley, 
  though 
  the 
  rocks 
  above 
  and 
  

   below 
  it 
  are 
  of 
  well 
  known 
  occurrence 
  outside 
  of 
  New 
  York. 
  

  

  Birdseye 
  Limestone 
  

  

  The 
  rock 
  which 
  succeeds 
  the 
  Chazy 
  limestone 
  is 
  one 
  well 
  known 
  

   in 
  the 
  Mohawk 
  valley, 
  as 
  well 
  known 
  along 
  the 
  Black 
  river 
  and 
  

  

  