﻿96 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  crushed 
  valves 
  of 
  small 
  plicated 
  brachiopods, 
  among 
  which 
  A 
  n 
  o 
  - 
  

   plotheca 
  hem 
  isph 
  erica 
  and 
  A. 
  p 
  1 
  i 
  c 
  a 
  t 
  u 
  1 
  a 
  may 
  be 
  

   mentioned. 
  Other 
  fossils 
  are 
  rarely 
  found 
  except 
  reed-like 
  impres- 
  

   sions 
  which 
  are 
  not 
  uncommon. 
  Some 
  impressions 
  have 
  been 
  found 
  

   which 
  probably 
  belong 
  to 
  Pterin 
  aea 
  emacerata, 
  a 
  pelecy- 
  

   pod 
  occurring 
  higher 
  in 
  the 
  Clinton 
  and 
  also 
  in 
  the 
  Rochester 
  

   shales. 
  The 
  total 
  thickness 
  of 
  these 
  shales 
  is 
  6 
  feet. 
  

  

  Clinton 
  lower 
  limestone. 
  On 
  the 
  shale 
  rests 
  a 
  stratum 
  of 
  lime- 
  

   stone 
  14-I 
  or 
  15 
  feet 
  in 
  thickness. 
  The 
  lower 
  three 
  or 
  four 
  feet 
  of 
  

   this 
  rock 
  are 
  compact 
  to 
  granular 
  or 
  finely 
  crystalline, 
  having 
  a 
  

   sugary 
  texture. 
  Small 
  masses 
  of 
  iron 
  pyrites 
  are 
  not 
  uncommon 
  

   in 
  this 
  rock, 
  this 
  being 
  the 
  only 
  representative 
  of 
  the 
  ferruginous 
  

   matter 
  so 
  characteristic 
  of 
  this 
  part 
  of 
  the 
  Clinton 
  beds 
  on 
  the 
  

   Genesee 
  river 
  and 
  eastward, 
  where 
  a 
  well 
  marked 
  bed 
  of 
  iron 
  ore 
  

   succeeds 
  the 
  shale. 
  Hall^ 
  states 
  that 
  " 
  the 
  lower 
  part 
  of 
  the 
  lime- 
  

   stone, 
  as 
  it 
  appears 
  on 
  the 
  Niagara 
  river, 
  is 
  highly 
  magnesian, 
  and 
  

   from 
  the 
  presence 
  of 
  iron 
  pyrites 
  rapidly 
  decomposes, 
  giving 
  rise 
  to 
  

   the 
  production 
  of 
  sulfate 
  of 
  magnesia, 
  which 
  at 
  favorable 
  points, 
  

   along 
  the 
  overhanging 
  mass 
  upon 
  the 
  river 
  bank, 
  may 
  be 
  collected 
  

   in 
  quantities 
  of 
  several 
  pounds." 
  

  

  Fossils 
  are 
  not 
  uncommon 
  in 
  this 
  division 
  of 
  the 
  Clinton 
  lime- 
  

   stone, 
  though 
  the 
  variety 
  is 
  not 
  very 
  great. 
  The 
  most 
  abundant 
  

   species 
  are 
  a 
  small 
  brachiopod, 
  Anoplotheca 
  plicatula 
  

   (fig. 
  133) 
  with 
  a 
  strongly 
  plicated 
  surface, 
  and 
  a 
  larger 
  flat 
  

   brachiopod, 
  Stropheodonta 
  profunda, 
  which 
  at 
  times 
  

   seems 
  scarcely 
  more 
  than 
  an 
  impression 
  on 
  the 
  rock 
  surface. 
  The 
  

   remaining 
  part 
  of 
  this 
  stratum 
  is 
  a 
  massive 
  dark 
  gray 
  limestone 
  

   with 
  occasional 
  thin 
  bands 
  of 
  a 
  shaly 
  character 
  separating 
  the 
  in- 
  

   dividual 
  beds. 
  Recognizable 
  fossils 
  are 
  not 
  very 
  abundant 
  in 
  this 
  

   rock. 
  Many 
  of 
  the 
  thin 
  bedded 
  portions 
  of 
  the 
  lower 
  Clinton 
  lime- 
  

   stone 
  contain 
  numerous 
  shining 
  black 
  phosphatic 
  nodules, 
  very 
  

   smooth 
  and 
  resembling 
  small 
  black 
  pebbles. 
  These 
  are 
  probabty 
  

   concretionary 
  masses, 
  though 
  some 
  have 
  the 
  aspect 
  of 
  being 
  water- 
  

   worn 
  organic 
  remains. 
  Where 
  the 
  thin 
  limestone 
  layers 
  are 
  covered 
  

   with 
  a 
  shaly 
  or 
  sandy 
  coating, 
  impressions 
  of 
  the 
  beautiful, 
  little 
  

  

  ^Rep't 
  4th 
  dist. 
  1842, 
  p. 
  6s. 
  

  

  