﻿The 
  Fauna 
  or 
  the 
  Niagara 
  Group. 
  101 
  

  

  while 
  the 
  Cystidse 
  are 
  almost 
  equally 
  conspicuous 
  with 
  the 
  

   Crinoidea. 
  At 
  the 
  Waldron 
  locality, 
  cystidean 
  forms 
  are 
  

   extremely 
  rare, 
  and 
  but 
  few 
  are 
  known 
  in 
  Tennessee 
  ; 
  and 
  

   though 
  not 
  abundant 
  in 
  New 
  York, 
  there 
  are 
  here 
  more 
  spe- 
  

   cies 
  known 
  than 
  in 
  both 
  the 
  other 
  localities 
  named. 
  I 
  con- 
  

   ceive, 
  however, 
  that 
  in 
  this 
  comparison 
  we 
  are 
  not 
  dealing 
  

   with 
  the 
  same 
  beds 
  in 
  each 
  one 
  of 
  these 
  localities. 
  While 
  

   I 
  regard 
  the 
  prevailing 
  fossiliferous 
  beds 
  in 
  western 
  New 
  

   York 
  as 
  essentially 
  parallel 
  with 
  those 
  of 
  Waldron 
  and 
  of 
  

   Western 
  Tennessee, 
  those 
  of 
  Wisconsin 
  and 
  Iowa 
  are 
  to 
  a 
  

   considerable 
  extent 
  of 
  newer 
  age, 
  being 
  the 
  higher 
  beds 
  of 
  

   the 
  series, 
  while 
  the 
  others 
  occupy 
  the 
  lower 
  and 
  middle 
  

   portions 
  of 
  the 
  formation.* 
  

  

  It 
  would 
  appear 
  from 
  what 
  we 
  know 
  of 
  the 
  physical 
  con- 
  

   ditions 
  of 
  this 
  ancient 
  sea, 
  that 
  it 
  was 
  generally 
  shallow 
  

   and 
  the 
  bottom 
  extremely 
  uneven. 
  

  

  The 
  Niagara 
  group 
  in 
  its 
  easterly 
  outcrop, 
  from 
  Eastern 
  New 
  

   York 
  to 
  Virginia, 
  indicates 
  a 
  nearly 
  uniform 
  shallow 
  sea, 
  

   with 
  the 
  deposition 
  of 
  calcareous 
  beds 
  of 
  magnesian 
  character, 
  

   which, 
  in 
  their 
  south-western 
  extension, 
  become 
  in 
  part 
  replaced 
  

   by, 
  or 
  alternate 
  with, 
  argillaceous 
  deposits. 
  Along 
  this 
  line 
  

   the 
  formation 
  is 
  everywhere 
  thin, 
  and, 
  in 
  fact, 
  is 
  so 
  inconspicu- 
  

   ous, 
  that 
  it 
  has 
  usually 
  been 
  considered 
  only 
  as 
  a 
  subordinate 
  

   member 
  of 
  the 
  succeeding 
  formation. 
  It 
  is 
  here 
  usually 
  

   marked 
  by 
  the 
  presence 
  of 
  a 
  few 
  species 
  of 
  corals, 
  which 
  are 
  

   extremely 
  abundant, 
  some 
  forms 
  of 
  brachiopods, 
  a 
  few 
  

   lamellibranchs, 
  gasteropods 
  and 
  cephalopods, 
  and 
  more 
  

   rarely 
  some 
  remains 
  of 
  trilobites. 
  These 
  are 
  of 
  forms 
  identi- 
  

   cal 
  with, 
  or 
  nearly 
  allied 
  to, 
  those 
  which 
  characterize 
  the 
  

   formation 
  in 
  its 
  more 
  western 
  localities. 
  In 
  a 
  westerly 
  direc- 
  

  

  * 
  The 
  relations 
  of 
  the 
  different 
  members 
  of 
  the 
  Niagara 
  formation, 
  in 
  Wiscon- 
  

   sin, 
  Iowa 
  and 
  other 
  western 
  localities, 
  with 
  those 
  of 
  New 
  York, 
  have 
  not 
  been 
  

   fully 
  determined. 
  It 
  is 
  known 
  that 
  in 
  Canada 
  West 
  the 
  limestones 
  of 
  the 
  lower 
  

   part 
  of 
  the 
  formation 
  acquire 
  a 
  greatly 
  increased 
  thickness 
  over 
  the 
  same 
  beds 
  in 
  

   Western 
  New 
  York 
  ; 
  and 
  that 
  they 
  likewise 
  include 
  the 
  limestones 
  of 
  the 
  Clin- 
  

   ton 
  group, 
  since 
  they 
  are 
  characterized 
  by 
  the 
  presence 
  of 
  Pentamerus 
  oblon- 
  

   gus 
  and 
  some 
  other 
  Clinton 
  forms 
  of 
  New 
  York. 
  In 
  their 
  western 
  extension 
  

   these 
  limestones 
  gradually 
  lose 
  their 
  shaly 
  partings 
  and 
  the 
  thin 
  seams 
  and 
  beds 
  

   of 
  shale, 
  becoming 
  massive 
  and 
  of 
  a 
  nearly 
  uniform 
  ashen 
  or 
  drab 
  color. 
  In 
  this 
  

   condition 
  the 
  entire 
  mass 
  is 
  recoguized 
  as 
  a 
  part 
  of 
  the 
  Niagara 
  formation, 
  and 
  

   the 
  Clinton 
  group 
  is 
  restricted 
  iu 
  its 
  acceptation 
  to 
  arenaceous 
  and 
  shaly 
  beds, 
  

   sometimes 
  with 
  thin 
  calcareous 
  bauds, 
  corresponding 
  more 
  nearly 
  in 
  physical 
  

   characters 
  with 
  the 
  same 
  formation 
  in 
  Herkimer 
  and 
  Oneida 
  counties 
  in 
  the 
  State 
  

   of 
  New 
  York. 
  

  

  