﻿44 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  New 
  York 
  is 
  wholly 
  lacking, 
  but 
  judging 
  by 
  the 
  occurrence 
  in 
  cen- 
  

   tral 
  Pennsylvania 
  of 
  rocks 
  of 
  the 
  same 
  age 
  as 
  the 
  Little 
  Falls 
  

   dolomite, 
  it 
  is 
  highly 
  probable 
  that 
  the 
  Little 
  Falls 
  sea 
  also 
  covered 
  

   western 
  and 
  southern 
  New 
  York. 
  

  

  The 
  Little 
  Falls 
  dolomite 
  is 
  especially 
  significant 
  in 
  two 
  ways 
  ; 
  

   first, 
  because 
  it 
  is 
  the 
  youngest 
  (uppermost) 
  Cambric 
  formation 
  in 
  

   the 
  State, 
  and 
  second, 
  there 
  is 
  a 
  distinct 
  unconformity 
  at 
  its 
  summit. 
  

   By 
  unconformity 
  here 
  we 
  mean 
  that, 
  after 
  the 
  deposition 
  of 
  the 
  

   dolomite, 
  at 
  least 
  all 
  of 
  northern 
  New 
  York 
  was 
  raised 
  (without 
  

   folding 
  or 
  faulting) 
  above 
  sea 
  level 
  and 
  underwent 
  erosion 
  for 
  a 
  

   moderate 
  length 
  of 
  time 
  after 
  which 
  most 
  of 
  the 
  region 
  again 
  set- 
  

   tled 
  below 
  sea 
  level 
  to 
  receive 
  the 
  deposits 
  of 
  later 
  (Ordovicic) 
  age. 
  

   This 
  old 
  eroded 
  surface 
  and 
  unconformity 
  has 
  been 
  well 
  established, 
  

   and 
  hence 
  we 
  learn 
  that 
  the 
  great 
  Cambric 
  period 
  of 
  the 
  early 
  

   Paleozoic 
  era 
  closed 
  with 
  all 
  of 
  northern 
  Nezv 
  York, 
  at 
  least, 
  well 
  

   above 
  sea 
  level. 
  In 
  southeastern 
  New 
  York, 
  so 
  far 
  as 
  known, 
  the 
  

   Cambric 
  strata 
  appear 
  to 
  grade 
  into 
  the 
  Ordovicic 
  and 
  if 
  so, 
  that 
  

   region 
  was 
  not 
  raised 
  above 
  sea 
  level 
  at 
  the 
  close 
  of 
  the 
  Cambric. 
  

   We 
  are 
  wholly 
  ignorant 
  as 
  to 
  the 
  physical 
  geography 
  of 
  western 
  

   and 
  southern 
  New 
  York 
  at 
  the 
  close 
  of 
  the 
  Cambric 
  because 
  the 
  

   records 
  there 
  are 
  not 
  accessible, 
  as 
  they 
  are 
  deeply 
  buried. 
  

  

  ORDOVICIC 
  PERIOD 
  

  

  We 
  are 
  now 
  ready 
  to 
  consider 
  the 
  physical 
  condition 
  of 
  the 
  State 
  

   during 
  the 
  great 
  Ordovicic 
  period 
  of 
  earth 
  history. 
  During 
  this 
  

   time 
  the 
  Appalachian 
  mountain 
  region, 
  the 
  great 
  Mississippi 
  valley, 
  

   and 
  much 
  of 
  the 
  far 
  western 
  region 
  were 
  almost 
  continually 
  under 
  

   water 
  (see 
  figure 
  16). 
  In 
  fact, 
  the 
  very. 
  widespread 
  distribution 
  of 
  

   thick 
  Ordovicic 
  strata 
  shows 
  that 
  more 
  of 
  North 
  America 
  was 
  

   covered 
  by 
  the 
  Ordovicic 
  sea 
  than 
  by 
  any 
  other 
  sea, 
  with 
  the 
  pos- 
  

   sible 
  exception 
  of 
  the 
  Precambric. 
  Among 
  -the 
  more 
  prominent 
  

   lands 
  which 
  persisted 
  above 
  water 
  were 
  Appalachia, 
  a 
  great 
  land 
  

   mass 
  occupying 
  what 
  is 
  now 
  the 
  Atlantic 
  sea 
  board 
  and 
  extending 
  

   an 
  unknown 
  distance 
  into 
  the 
  Atlantic, 
  and 
  another 
  large 
  land 
  area 
  

   in 
  the 
  Hudson 
  Bay 
  region 
  of 
  Canada. 
  Sediments 
  from 
  those 
  lands 
  

   were 
  washed 
  into 
  the 
  Ordovicic 
  sea 
  which, 
  for 
  most 
  part 
  at 
  least, 
  

   covered 
  the 
  State 
  during 
  the 
  entire 
  period. 
  In 
  eastern 
  and 
  south- 
  

   eastern 
  New 
  York, 
  the 
  almost 
  unbroken 
  succession 
  of 
  Ordovicic 
  

   strata 
  shows 
  that 
  the 
  sea 
  was 
  much 
  of 
  the 
  time 
  present 
  there 
  

   during 
  the 
  entire 
  period. 
  The 
  prominent 
  development 
  of 
  Ordovicic 
  

   strata 
  west 
  and 
  south 
  of 
  New 
  York 
  makes 
  it 
  practically 
  certain 
  

  

  