﻿4 
  

  

  NIAGARA 
  FALLS 
  AND 
  VICINITY 
  155 
  

  

  with 
  Eucalyptocrinus 
  fragments 
  and 
  other 
  crinoids, 
  as 
  well 
  

  

  as 
  other 
  fossils. 
  

  

  Stephanocrinus 
  gemmiformis 
  Hall 
  (Fig. 
  49) 
  (1852. 
  Pal. 
  N. 
  Y. 
  

  

  2:215, 
  pi. 
  48) 
  

  

  Distinguishing 
  characters. 
  Sharply 
  

  

  triangular 
  base; 
  rapidly 
  enlarging 
  

   - 
  . 
  calyx, 
  which 
  is 
  rotund 
  in 
  the 
  middle 
  

   / 
  and 
  slightly 
  contracted 
  toward 
  the 
  sum- 
  

   mit. 
  Upper 
  margin 
  of 
  radials 
  scarcely 
  

   depressed 
  or 
  excavated; 
  granular 
  non- 
  

   Fig. 
  49 
  stephanocrinus 
  gPmmiformis 
  carluatc 
  surfacc 
  of 
  plates; 
  slightly 
  con- 
  

  

  with 
  analj^sis 
  of 
  calyx 
  . 
  . 
  

  

  vergmg 
  coronal 
  processes. 
  

   Found 
  in 
  the 
  Rochester 
  shale 
  at 
  Lockport 
  (Hall). 
  Probably 
  also 
  

   at 
  Niagara. 
  

  

  Order 
  cA?vd:K^R>?s.T^ 
  Wachsmuth 
  & 
  Springer 
  

   Genus 
  thysanocrinus 
  Flail 
  

   [Ety. 
  : 
  Oufjdxx^ 
  , 
  fringe; 
  xfityoy, 
  lily] 
  

   (1852. 
  Pal. 
  N. 
  Y. 
  2:188) 
  

  

  Calyx 
  deep, 
  with 
  a 
  dicyclic 
  base. 
  Infrabasals 
  and 
  basals 
  five 
  

   each, 
  the 
  former 
  pentagonal, 
  the 
  latter 
  generally 
  hexagonal. 
  Radials 
  

  

  ]^9^i 
  

  

  / 
  

  

  A 
  1& 
  

  

  A 
  

  

  

  

  

  Fig. 
  50 
  Thysanocrinus 
  lililformis 
  with 
  analysis 
  of 
  calyx 
  

  

  five, 
  hexagonal, 
  laterally 
  in 
  contact, 
  except 
  at 
  the 
  azygous 
  side, 
  where 
  

   they 
  are 
  separated 
  by 
  an 
  anal 
  plate 
  which 
  is 
  succeeded 
  by 
  three 
  in- 
  

  

  