﻿126 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  the 
  actually 
  exposed 
  sections 
  of 
  these 
  limestone 
  strata 
  are 
  very 
  few 
  

   when 
  compared 
  with 
  the 
  great 
  extent 
  of 
  the 
  beds 
  themselves. 
  It 
  

   must 
  also 
  be 
  borne 
  in 
  mind, 
  that 
  vast 
  portions 
  of 
  these 
  limestone 
  

   beds 
  have 
  been 
  removed 
  by 
  erosion 
  during 
  the 
  long 
  post-Siluric 
  

   time. 
  When 
  we 
  realize 
  that 
  the 
  actual 
  reefs 
  must 
  have 
  been 
  widely 
  

   scattered 
  in 
  the 
  Niagara 
  sea, 
  and 
  that 
  our 
  sections 
  through 
  these 
  

   strata 
  are 
  random 
  sections, 
  we 
  need 
  feel 
  no 
  surprise 
  at 
  the 
  unsatis- 
  

   factory 
  character 
  of 
  these 
  exposures. 
  It 
  must 
  however 
  be 
  added 
  

   that 
  sections 
  farther 
  east, 
  as 
  at 
  Lockport 
  or 
  other 
  localities, 
  gen- 
  

   erally 
  show 
  much 
  more 
  of 
  the 
  reef 
  character 
  of 
  the 
  deposit, 
  the 
  

   corals 
  in 
  these 
  being 
  correspondingly 
  abundant. 
  The 
  upper 
  

   geodiferous 
  beds 
  of 
  the 
  limestone 
  at 
  Niagara 
  were 
  probably 
  much 
  

   more 
  fossiliferous 
  than 
  the 
  lower. 
  As 
  before 
  mentioned^ 
  the 
  geode 
  

   cavities 
  most 
  likely 
  are 
  the 
  result 
  of 
  alteration 
  or 
  solution 
  of 
  some 
  

   fossil 
  body, 
  probably 
  a 
  coral. 
  Though 
  fossils 
  may 
  have 
  been 
  plenti- 
  

   ful, 
  none 
  of 
  these 
  beds, 
  so 
  far 
  as 
  examined, 
  show 
  the 
  characteristics 
  

   of 
  true 
  reefs. 
  They 
  have 
  more 
  the 
  aspect 
  of 
  beds 
  of 
  coral 
  sand, 
  

   on 
  which 
  isolated 
  heads 
  of 
  corals 
  and 
  other 
  organisms 
  grew 
  rather 
  

   plentifully. 
  

  

  During 
  the 
  dolomitization 
  of 
  these 
  limestone 
  beds, 
  which 
  was 
  

   probably 
  brought 
  about 
  by 
  chemical 
  substitution 
  before 
  the 
  con- 
  

   solidation 
  of 
  the 
  coral 
  sand, 
  many 
  of 
  the 
  fossils 
  which 
  were 
  included 
  

   in 
  these 
  sands 
  probably 
  suffered 
  alteration 
  and 
  more 
  or 
  less 
  com- 
  

   plete 
  destruction. 
  Thus 
  it 
  will 
  be 
  seen 
  that 
  even 
  the 
  few 
  organisms 
  

   which 
  were 
  embedded 
  in 
  these 
  coral 
  sands, 
  did 
  not 
  survive 
  the 
  sub- 
  

   sequent 
  changes, 
  and 
  thus 
  the 
  barrenness 
  of 
  these 
  great 
  limestone 
  

   masses 
  appears 
  to 
  be 
  fully 
  accounted 
  for. 
  The 
  fossiliferous 
  char- 
  

   acter 
  of 
  the 
  upper 
  Clinton 
  limestone, 
  as 
  well 
  as 
  the 
  coarseness 
  of 
  

   the 
  calcareous 
  fragments 
  of 
  which 
  it 
  is 
  composed, 
  points 
  to 
  a 
  near- 
  

   ness 
  of 
  this 
  rock 
  to 
  the 
  source 
  of 
  the 
  material; 
  for 
  in 
  the 
  vicinity 
  of 
  

   the 
  coral 
  and 
  crinoid 
  reefs 
  the 
  food 
  supply 
  for 
  other 
  organisms 
  

   would 
  be 
  most 
  abundant, 
  and 
  hence 
  these 
  would 
  develop 
  most 
  pro- 
  

   lifically 
  in 
  such 
  a 
  neighborhood. 
  

  

  A 
  careful 
  comparative 
  study 
  of 
  the 
  Niagaran 
  deposits 
  of 
  New 
  

   York 
  and 
  those 
  of 
  the 
  middle 
  states 
  has 
  brought 
  out 
  some 
  im- 
  

   portant 
  and 
  interesting 
  facts. 
  These 
  may 
  be 
  summed 
  up 
  in 
  the 
  

  

  