﻿STRATIGRAPHIC 
  GEOLOGY 
  OF 
  THE 
  EASTERN 
  HELDERBERGS 
  343 
  

  

  of 
  this 
  cut 
  is 
  a 
  fall 
  of 
  about 
  20 
  feet, 
  an 
  unusual 
  feature 
  in 
  the 
  

   shaly 
  formation. 
  The 
  gorge 
  is 
  fully 
  a 
  quarter 
  of 
  a 
  mile 
  long 
  and 
  

   is 
  the 
  finest 
  exposure 
  of 
  the 
  shaly 
  that 
  the 
  writer 
  has 
  ever 
  seen. 
  

  

  There 
  is 
  a 
  gorge 
  through 
  the 
  Onondaga 
  about 
  200 
  yards 
  north 
  

   of 
  the 
  one 
  through 
  which 
  the 
  Oniskethau 
  now 
  flows 
  and 
  some- 
  

   what 
  smaller 
  than 
  it, 
  which 
  the 
  writer 
  considers 
  to 
  be 
  an 
  ancient 
  

   bed 
  of 
  this 
  creek. 
  Its 
  situation 
  is 
  such 
  that 
  the 
  creek 
  might 
  

   easily 
  be 
  turned 
  into 
  it 
  now 
  and 
  there 
  is 
  no 
  other 
  stream 
  in 
  the 
  

   vicinity 
  large 
  enough 
  to 
  have 
  cut 
  such 
  a 
  gorge. 
  At 
  the 
  lower 
  end 
  

   of 
  the 
  village 
  west 
  of 
  the 
  Dutch 
  reformed 
  church 
  is 
  another 
  evi- 
  

   dence 
  of 
  this 
  ancient 
  bed. 
  It 
  is 
  a 
  little 
  valley 
  running 
  north 
  and 
  

   south, 
  the 
  highest 
  part 
  of 
  which 
  is 
  not 
  more 
  than 
  10 
  feet 
  above 
  

   the 
  present 
  bed 
  of 
  the 
  Oniskethau, 
  and 
  before 
  the 
  gorge 
  was 
  cut 
  

   to 
  the 
  east 
  this 
  valley 
  must 
  have 
  been 
  the 
  outlet 
  to 
  the 
  little 
  lake 
  

   which 
  formerly 
  existed 
  at 
  Clarksville. 
  

  

  Along 
  the 
  base 
  of 
  Bennett 
  hill 
  immediately 
  south 
  of 
  the 
  village 
  

   are 
  seen 
  the 
  northernmost 
  traces 
  of 
  these 
  flexures 
  which 
  are 
  so 
  ap- 
  

   parent 
  in 
  these 
  formations 
  farther 
  south. 
  a 
  They 
  consist 
  of 
  two 
  

   slight 
  folds 
  and 
  a 
  small 
  overthrust. 
  The 
  overthrust 
  is 
  in 
  the 
  

   gorge 
  through 
  the 
  Onondaga 
  above 
  the 
  village 
  and 
  may 
  be 
  plain- 
  

   ly 
  seen 
  on 
  its 
  eastern 
  side. 
  There 
  is 
  a 
  layer 
  of 
  Schoharie 
  grit 
  

   with 
  Onondaga 
  limestone 
  dipping 
  under 
  it, 
  8 
  or 
  10 
  feet 
  of 
  the 
  

   limestone 
  being 
  exposed, 
  while 
  above 
  the 
  Schoharie 
  lies 
  the 
  regu- 
  

   lar 
  thickness 
  of 
  Onondaga. 
  A 
  number 
  of 
  fissures 
  filled 
  with 
  cal- 
  

   cite, 
  made 
  no 
  doubt 
  when 
  the 
  overthrust 
  occurred, 
  may 
  be 
  seen 
  in 
  

   the 
  gorge. 
  One 
  of 
  the 
  folds 
  consisting 
  of 
  a 
  broad, 
  low 
  anticline 
  

   is 
  very 
  evident 
  in 
  the 
  sides 
  of 
  the 
  gorge 
  through 
  the 
  Esopus 
  

   shales 
  below 
  the 
  village. 
  The 
  other 
  fold 
  is 
  between 
  the 
  two 
  

   gorges 
  east 
  of 
  the 
  house 
  of 
  Mr 
  W. 
  H. 
  Eowe. 
  

  

  Clarksville 
  like 
  all 
  the 
  Helderberg 
  region 
  has 
  been 
  visited 
  by 
  

   many 
  geologists. 
  Among 
  the 
  first 
  must 
  have 
  been 
  Mr 
  T. 
  A. 
  

   Conrad 
  for 
  he 
  used 
  the 
  name 
  Clarksville 
  for 
  two 
  formations 
  in 
  

   his 
  Section 
  of 
  New 
  York 
  Silurian 
  rocks. 
  That 
  part 
  of 
  Mr 
  Conrad's 
  

   section 
  in 
  which 
  this 
  name 
  is 
  used 
  is 
  as 
  follows: 
  

  

  aAppalachia. 
  1884. 
  3:20-33. 
  Plate. 
  

  

  