﻿FIFTH 
  REPORT 
  OF 
  THE 
  DIRECTOR 
  I908 
  33 
  

  

  facies. 
  In 
  favor 
  of 
  this 
  view 
  it 
  may 
  be 
  said 
  that 
  both 
  formations 
  

   rest 
  on 
  the 
  same 
  basis 
  (Cambric 
  and 
  Lower 
  Siluric 
  slate) 
  and 
  

   that, 
  on 
  account 
  of 
  the 
  rising 
  of 
  the 
  Taconic 
  mountains 
  in 
  early 
  

   Siluric 
  time, 
  there 
  may 
  have 
  existed 
  a 
  littoral 
  facies 
  of 
  the 
  Helder- 
  

   berg- 
  rocks 
  to 
  the 
  east. 
  But 
  this 
  view 
  is 
  strongly 
  opposed 
  by 
  the 
  

   fact 
  that 
  the 
  Helderberg 
  rocks 
  do 
  not 
  show 
  any 
  indications 
  of 
  

   approach 
  to 
  a 
  littoral 
  region 
  at 
  Becraft 
  mountain, 
  but 
  retain 
  the 
  

   same 
  lithologic 
  'characters 
  that 
  they 
  possess 
  over 
  a 
  vast 
  area. 
  

   There 
  would 
  hence 
  have 
  to 
  be 
  assumed 
  an 
  extremely 
  abrupt 
  and 
  

   improbable 
  change 
  in 
  facies 
  in 
  the 
  short 
  distance 
  of 
  20 
  miles 
  from 
  

   Becraft 
  mountain 
  to 
  the 
  outlier 
  at 
  Austerlitz. 
  A 
  somewhat 
  dif- 
  

   ferent 
  cause 
  is 
  presented 
  by 
  the 
  Oriskany 
  sandstone, 
  Esopus 
  grit 
  

   and 
  Schoharie 
  grit 
  which 
  not 
  only 
  contain 
  sand 
  and 
  grit 
  at 
  

   Becraft 
  mountain 
  and 
  in 
  the 
  Helderbergs, 
  but 
  in 
  some 
  places, 
  as 
  at 
  

   Whiteport 
  and 
  Kingston, 
  contain 
  conglomerate 
  beds. 
  It 
  is 
  alto- 
  

   gether 
  probable 
  that 
  the 
  material 
  of 
  these 
  conglomerates 
  was 
  

   derived 
  from 
  the 
  south 
  and 
  the 
  Oriskany 
  sandstone 
  is 
  too 
  thin 
  a 
  

   layer 
  (30 
  feet) 
  at 
  Becraft 
  mountain, 
  to 
  be 
  correlated 
  with 
  the 
  thick 
  

   mass 
  of 
  the 
  Rensselaer 
  grit 
  (1400 
  feet). 
  It 
  is, 
  however, 
  possible 
  

   that 
  the 
  Esopus 
  and 
  Schoharie 
  grits 
  which 
  at 
  Becraft 
  mountain 
  

   have 
  a 
  combined 
  thickness 
  of 
  300 
  feet 
  and 
  are 
  similarly 
  barren 
  in 
  

   fossils, 
  once 
  continued 
  northeastward 
  into 
  the 
  Rensselaer 
  grit 
  

   trough. 
  Since 
  they 
  represent 
  an 
  invasion 
  of 
  the 
  sea 
  that 
  came 
  from 
  

   the 
  south 
  and 
  spread 
  northward 
  in 
  the 
  direction 
  of 
  the 
  Rensselaer 
  

   grit 
  plateau, 
  and 
  the 
  overlapping 
  Rensselaer 
  grit 
  is 
  clearly 
  the 
  

   product 
  of 
  an 
  invading, 
  not 
  a 
  receding, 
  sea, 
  it 
  is 
  a 
  reasonable 
  propo- 
  

   sition 
  that 
  the 
  Rensselaer 
  grit 
  was 
  deposited 
  in 
  a 
  long 
  narrow 
  

   embayment 
  extending 
  northward 
  from 
  the 
  OriskauA'-Esopus- 
  

   Schoharie 
  grit 
  sea 
  of 
  southern 
  New 
  York. 
  But 
  in 
  this 
  case 
  also, 
  

   there 
  is 
  still 
  to 
  be 
  explained 
  the 
  extremely 
  rapid 
  change 
  from 
  the 
  

   .typical 
  Esopus 
  grit 
  of 
  Becraft 
  mountain 
  to 
  the 
  red 
  and 
  green 
  

   slates 
  and 
  coarse 
  grits 
  of 
  the 
  Austerlitz 
  outlier, 
  and 
  the 
  fact 
  that 
  the 
  

   Esopus 
  grit 
  is 
  thicker 
  southward 
  (700 
  feet 
  in 
  Orange 
  county), 
  and 
  

   thins 
  out 
  toward 
  Becraft 
  mountain. 
  The 
  regular 
  succession 
  of 
  the 
  

   various 
  members 
  of 
  the 
  Lower 
  and 
  ^liddle 
  Devonic 
  in 
  Becraft 
  

   mountain 
  with 
  the 
  same 
  lithologic 
  characters 
  as 
  in 
  the 
  Helderbergs 
  

   and 
  much 
  farther 
  west 
  and 
  south 
  is 
  in 
  itself 
  cumulative 
  evidence 
  

   that 
  the 
  Helderberg 
  sea 
  extended 
  farther 
  east 
  than 
  the 
  present 
  

   Rensselaer 
  plateau 
  and 
  with 
  unchanged 
  or 
  but 
  little 
  changed 
  

   conditions. 
  

  

  It 
  must 
  further 
  be 
  considered 
  that 
  the 
  Rensselaer 
  grit 
  plateau 
  

  

  