﻿102 
  TWEKTT-EIGHTH 
  EEPORT 
  0^ 
  THE 
  STATE 
  MUSEUM. 
  

  

  tion, 
  within 
  the 
  limits 
  of 
  New 
  York, 
  the 
  formation 
  has 
  a 
  

   very 
  moderate 
  development 
  nntil 
  we 
  reach 
  the 
  eastern 
  part 
  

   of 
  Wayne 
  county, 
  where 
  the 
  shaly 
  member 
  of 
  the 
  formation 
  

   becomes 
  marked 
  and 
  gradually 
  increases 
  in 
  thickness 
  to 
  

   Niagara 
  county; 
  the 
  superior 
  limestone 
  increasing 
  in 
  thick- 
  

   ness 
  in 
  the 
  same 
  direction. 
  The 
  shaly 
  fossiliferous 
  beds, 
  which 
  

   are 
  so 
  conspicuous 
  a 
  feature 
  on 
  the 
  Genesee 
  River 
  at 
  Roches- 
  

   ter, 
  in 
  Wayne 
  and 
  Niagara 
  counties, 
  and 
  upon 
  the 
  Niagara 
  

   river, 
  thin 
  out 
  to 
  a 
  great 
  extent 
  within 
  fifty 
  miles 
  west 
  of 
  

   the 
  river, 
  and 
  are 
  nowhere 
  met 
  with 
  along 
  the 
  outcrops 
  in 
  a 
  

   westerly 
  and 
  north-westerly 
  direction. 
  This 
  shaly 
  member 
  of 
  

   the 
  formation 
  was 
  apparently 
  deposited 
  in 
  a 
  wide, 
  shallow 
  de- 
  

   pression 
  in 
  the 
  bed 
  of 
  the 
  ancient 
  ocean, 
  which 
  became 
  

   gradually 
  rilled 
  with 
  fine 
  calcareous 
  mud, 
  and 
  which, 
  during 
  

   this 
  slow 
  process, 
  afforded 
  opportunity 
  for 
  the 
  development 
  

   of 
  a 
  most 
  abundant 
  fauna, 
  

  

  In 
  Indiana, 
  also, 
  these 
  shaly 
  beds 
  were 
  probably 
  deposited 
  

   in 
  a 
  wide 
  depression 
  of 
  the 
  ocean 
  bed, 
  similar 
  to 
  that 
  of 
  

   western 
  New 
  York, 
  while 
  the 
  area 
  to 
  the 
  northward 
  was 
  

   a 
  more 
  shallow 
  sea. 
  We 
  have 
  a 
  less 
  accurate 
  knowledge 
  of 
  

   the 
  physical 
  conditions 
  which 
  prevailed 
  to 
  the 
  south 
  and 
  south- 
  

   west 
  of 
  the 
  localities 
  named 
  ; 
  but 
  it 
  would 
  appear, 
  from 
  what 
  

   we 
  know 
  of 
  the 
  distribution 
  of 
  the 
  fossils, 
  that 
  there 
  were 
  

   similar 
  areas 
  of 
  depression 
  with 
  a 
  most 
  abundant 
  fauna, 
  while 
  

   the 
  intermediate 
  shallower 
  areas 
  are 
  marked 
  by 
  the 
  presence 
  

   of 
  calcareous 
  deposits, 
  with 
  a 
  moderate 
  development 
  of 
  a 
  some- 
  

   what 
  distinct 
  fauna, 
  in 
  which 
  corals 
  are 
  usually 
  conspicuous, 
  

   and 
  carrying 
  the 
  aspect 
  of 
  an 
  interrupted 
  and 
  imperfectly 
  

   developed 
  coral 
  reef. 
  

  

  