﻿Report 
  of 
  the 
  State 
  Geologist. 
  345 
  

  

  71 
  

  

  From 
  this 
  point 
  to 
  954 
  grey 
  limestones 
  alternate 
  with 
  

   continuous 
  or 
  nodular 
  layers 
  of 
  chert. 
  The 
  former 
  are 
  from 
  

   one-half 
  to 
  five 
  feet 
  in 
  thickness 
  and 
  vary 
  little 
  in 
  lithological 
  

   character 
  or 
  in 
  the 
  nature 
  of 
  the 
  fossils. 
  The 
  alternation 
  of 
  

   limestone 
  and 
  chert 
  is 
  irregular, 
  the 
  latter 
  usually 
  in 
  thin 
  

   layers, 
  but 
  the 
  amount 
  of 
  chert 
  gradually 
  increases 
  downward. 
  

  

  At 
  888 
  is 
  the 
  remarkable 
  layer, 
  four 
  inches 
  thick, 
  composed 
  

   of 
  a 
  mass 
  of 
  crystal 
  scales 
  of 
  gypsum 
  in 
  an 
  amorphic 
  gypsum 
  

   base. 
  This 
  is 
  in 
  juxtaposition 
  on 
  its 
  upper 
  surface 
  with 
  a 
  

   very 
  thin 
  layer 
  of 
  comminuted 
  crinoids. 
  

  

  Few 
  fossils 
  have 
  been 
  observed 
  in 
  the 
  chert. 
  The 
  pre- 
  

   dominant 
  forms 
  in 
  the 
  limestone 
  are: 
  Phacops 
  pipa, 
  JEuom- 
  

   phalus 
  sp. 
  nov.?, 
  Chonetes 
  lineata, 
  Atrypa 
  reticularis, 
  

   Goelospira 
  Camilla, 
  Amboccelia 
  umbonata, 
  a 
  very 
  small 
  

   variety 
  in 
  masses 
  at 
  943. 
  

  

  Common 
  species 
  are: 
  

  

  Proetus 
  clarus, 
  Odo?itocephalus 
  seleaurus, 
  Orthis 
  lenti- 
  

   cularis, 
  Stropheodonta 
  hemisphcerica, 
  P. 
  incequistriata, 
  

   Orthothetes 
  Pandora, 
  Leptmna 
  rhomboidalis, 
  Athyris 
  

   spiriferoides. 
  

  

  The 
  following 
  are 
  rarely 
  observed: 
  

  

  CyrtoGeras 
  sp.?, 
  Gyroceras 
  trivolveP, 
  Orthoceras 
  tetricum, 
  

   Platyceras 
  sp, 
  nov., 
  Stropheodonta 
  perplana, 
  Spirifer 
  duo- 
  

   denarius, 
  S. 
  ftmbriatics, 
  Aviculopecten 
  sp.? 
  

  

  44 
  

  

  