﻿96 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  began 
  in 
  the 
  Champlain 
  region, 
  and 
  what 
  has 
  there 
  been 
  called 
  

   Black 
  River 
  limestone 
  commenced 
  its 
  accumulation. 
  This 
  deposit 
  

   consists 
  of 
  a 
  small 
  thickness 
  of 
  typical 
  Lowville 
  at 
  the 
  base, 
  the 
  

   equivalent 
  of 
  the 
  Leray 
  limestone 
  at 
  the 
  summit, 
  and 
  interme- 
  

   diate 
  beds 
  which 
  represent 
  the 
  Lowville-Leray 
  hiatus 
  of 
  the 
  north- 
  

   west; 
  while 
  the 
  Watertown 
  limestone 
  is 
  lacking. 
  With 
  our 
  sug- 
  

   gested 
  nomenclature 
  this 
  may 
  still 
  be 
  properly 
  called 
  Black 
  River, 
  

   while 
  on 
  any 
  other 
  arrangement 
  it 
  could 
  not 
  be 
  so 
  called. 
  The 
  

   Mohawk 
  region 
  was 
  close 
  to 
  the 
  shore 
  line 
  throughout 
  Black 
  River 
  

   time 
  and 
  received 
  only 
  the 
  very 
  thin, 
  near-shore 
  edge 
  oi 
  the 
  deposits 
  

   of 
  the 
  group, 
  never 
  more 
  than 
  a 
  few 
  feet 
  thick, 
  often 
  practically 
  

   absent 
  and 
  varying 
  much 
  in 
  horizon 
  from 
  place 
  to 
  place. 
  

  

  At 
  the 
  close 
  of 
  the 
  Leray, 
  uphft 
  was 
  widespread 
  and 
  the 
  Water- 
  

   town 
  limestone 
  is 
  practically 
  absent 
  except 
  in 
  that 
  locality, 
  in 
  strong 
  

   contrast 
  with 
  the 
  widespread 
  occurrence 
  of 
  the 
  preceding 
  Leray. 
  

   Then 
  followed 
  subsidence 
  on 
  the 
  east 
  with 
  accumulation 
  of 
  the 
  

   Amsterdam 
  limestone, 
  which 
  is 
  wholly 
  absent 
  on 
  the 
  west. 
  Then 
  

   ensued 
  on 
  all 
  sides 
  of 
  the 
  region 
  the 
  Trenton 
  submergence; 
  lime- 
  

   stone 
  quickly 
  followed 
  by 
  black 
  shale 
  on 
  the 
  east 
  so 
  that 
  the 
  bulk 
  

   of 
  the 
  eastern 
  Trenton 
  is 
  of 
  shale; 
  the 
  shale 
  gradually 
  encroaching 
  

   westward, 
  but 
  the 
  western 
  Trenton, 
  of 
  the 
  type 
  locality 
  and 
  north- 
  

   ward, 
  remaining 
  of 
  limestone 
  throughout. 
  The 
  black 
  shale 
  of 
  the 
  

   Utica 
  followed, 
  with 
  northern 
  New 
  York 
  -more 
  largely 
  submerged 
  

   than 
  at 
  any 
  other 
  period 
  in 
  its 
  geologic 
  history, 
  the 
  Grenville 
  pos- 
  

   sibly 
  excepted. 
  Possibly 
  the 
  Adirondack 
  island 
  was 
  entirely 
  sub- 
  

   merged. 
  With 
  the 
  close 
  of 
  the 
  Utica 
  local 
  elevations 
  began 
  to 
  ap- 
  

   pear, 
  and 
  by 
  the 
  close 
  of 
  the 
  Ordovicic 
  much 
  of 
  the 
  State 
  was 
  again 
  

   unsubmerged. 
  Since 
  then 
  most 
  of 
  northern 
  New 
  York 
  has 
  re- 
  

   mained 
  a 
  land 
  area. 
  The 
  appended 
  chart 
  will, 
  it 
  is 
  hoped, 
  aid 
  in 
  

   the 
  understanding 
  of 
  these 
  views. 
  

  

  