﻿214 
  NEW 
  YORK 
  STATE- 
  MUSEUM 
  

  

  of 
  geological 
  mapping 
  and 
  consequently 
  that 
  has 
  been 
  taken 
  for 
  

   the 
  base 
  of 
  the 
  Oneonta 
  formation. 
  

  

  - 
  Along 
  the 
  Schoharie 
  valley 
  there 
  is 
  an 
  alternation 
  of 
  the 
  litho- 
  

   logic 
  characters 
  and 
  faunas 
  characterizing 
  the 
  Ithaca 
  and 
  

   Oneonta 
  formations 
  for 
  several 
  hundred 
  feet. 
  In 
  the 
  greenish 
  

   sandstones 
  at 
  the 
  Manorkill 
  or 
  along 
  the 
  Schoharie 
  near 
  Gilboa, 
  

   Amnigenia 
  catshillensis 
  (Van.) 
  Hall 
  was 
  not 
  found 
  in 
  place; 
  but 
  

   specimens 
  were 
  found 
  in 
  large 
  blocks 
  of 
  this 
  sandstone 
  along 
  the 
  

   bank 
  of 
  the 
  river 
  which 
  probably 
  came 
  from 
  these 
  sandstones. 
  

   Considerably 
  higher 
  above 
  these 
  red 
  and 
  greenish 
  gray 
  sand- 
  

   stones 
  a 
  meager 
  Ithaca 
  fauna 
  was 
  found 
  at 
  several 
  places 
  in 
  

   the 
  Schoharie 
  and 
  Manorkill 
  valleys. 
  It 
  was 
  not 
  satisfactorily 
  

   determined 
  whether 
  these 
  highest 
  fossiliferous 
  layers 
  occur 
  at 
  a 
  

   higher 
  stratigraphic 
  position 
  than 
  the 
  top 
  of 
  the 
  Ithaca 
  fauna 
  in 
  

   the 
  Susquehanna 
  valley, 
  but 
  it 
  is 
  clear 
  that 
  the 
  lithologic 
  con- 
  

   ditions 
  of 
  the 
  Oneonta 
  formation 
  appear 
  at 
  a 
  lower 
  stratigraphic 
  

   position 
  in 
  the 
  Schoharie 
  than 
  in' 
  the 
  Susquehanna 
  valley 
  and 
  that 
  

   there 
  is 
  an 
  alternation 
  of 
  these 
  conditions 
  through 
  a 
  thickness 
  

   of 
  several 
  hundred 
  feet 
  of 
  rocks. 
  The 
  Schoharie 
  section 
  is 
  along 
  

   the 
  region 
  of 
  oscillation, 
  between 
  the 
  marine 
  waters 
  with 
  the 
  

   Ithaca 
  fauna 
  of 
  the 
  west 
  and 
  the 
  brackish 
  waters 
  of 
  the 
  east. 
  

   In 
  the 
  Susquehanna 
  valley 
  during 
  this 
  time, 
  marine 
  waters 
  pre- 
  

   vailed 
  as 
  shown 
  by 
  the 
  faunas, 
  and 
  there 
  is 
  no 
  evidence 
  of 
  the 
  

   brackish 
  waters; 
  while 
  in 
  Albany 
  and 
  Greene 
  counties 
  the 
  brack- 
  

   ish 
  waters 
  dominated 
  and 
  there 
  is 
  scarcely 
  any 
  evidence 
  of 
  marine 
  

   faunas. 
  

  

  LXXV 
  A 
  1 
  . 
  This 
  section 
  extends 
  from 
  the 
  Schoharie 
  river 
  at 
  the 
  

   Gilboa 
  bridge 
  along 
  the 
  highway 
  toward 
  Grand 
  Gorge 
  for 
  more 
  

   than 
  one 
  mile, 
  and 
  then 
  to 
  the 
  top 
  of 
  the 
  hill 
  about 
  south 
  of 
  Gilboa. 
  

   It 
  is 
  an 
  especially 
  interesting 
  one 
  since 
  it 
  shows 
  the 
  presence 
  of 
  

   a 
  fauna 
  with 
  a 
  considerable 
  number 
  of 
  species, 
  ov«r 
  400 
  feet 
  

   above 
  the 
  river 
  level 
  and 
  the 
  first 
  stratum 
  of 
  red 
  rocks 
  at 
  Gilboa. 
  

   The 
  lower 
  part 
  of 
  the 
  section 
  (A 
  1 
  ) 
  is 
  pretty 
  well 
  covered, 
  but 
  there 
  

   are 
  some 
  outcrops 
  which 
  give 
  a 
  general 
  idea 
  of 
  the 
  lithologic 
  char- 
  

   acters 
  of 
  the 
  rocks. 
  At 
  the 
  base 
  are 
  massive 
  sandstones, 
  above 
  

  

  