﻿1 
  86 
  

  

  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  valve 
  elevated 
  and 
  somewhat 
  incurved; 
  dental 
  lamellae 
  slightly 
  de- 
  

   veloped, 
  not 
  extending 
  the 
  entire 
  length 
  of 
  the 
  umbonal 
  cavity. 
  Car- 
  

   dinal 
  process 
  an 
  elongate 
  vertical 
  plate, 
  logitudinally 
  dividing 
  the 
  

   deep 
  deltidial 
  cavity. 
  

  

  Orthis 
  flabellites 
  Foerste 
  

   (Fig. 
  94). 
  Orthis 
  f 
  1 
  a 
  - 
  

   b 
  e 
  1 
  1 
  u 
  1 
  u 
  m 
  var. 
  Hall 
  (1852. 
  

   Pal. 
  N. 
  7.2:254, 
  pi. 
  52) 
  

   Distill 
  o-uishin 
  s" 
  characters. 
  

  

  Fig. 
  94 
  Orthis 
  flabellites 
  

  

  Long 
  hinge 
  line; 
  semioval 
  

   form; 
  coarse, 
  simple 
  rounded 
  

   plications, 
  equal 
  to 
  spaces 
  

   between 
  them; 
  marked 
  con- 
  

   centric 
  growth 
  lines. 
  

  

  Found 
  in 
  the 
  upper 
  Clinton 
  

  

  limestone 
  and 
  the 
  lower 
  Rochester 
  shale 
  at 
  Niagara. 
  Rare. 
  Also 
  

  

  in 
  the 
  shale 
  at 
  Lockport 
  (Hall). 
  

  

  . 
  Orthis 
  ( 
  ?) 
  punctostriata 
  Hall 
  (Fig. 
  95) 
  

  

  (1852. 
  Pal. 
  N. 
  Y'. 
  2:254, 
  pi. 
  52, 
  fig. 
  5a-f) 
  

   Distinguishing 
  characters. 
  Subglobose 
  

  

  contour, 
  nearly 
  equal, 
  extremely 
  convex 
  

  

  valves; 
  beak 
  of 
  pedicle 
  valve 
  somewhat 
  

  

  longer 
  than 
  that 
  of 
  brachial 
  valve, 
  but 
  both 
  

  

  prominent; 
  short 
  hinge 
  line, 
  still 
  shorter 
  

  

  but 
  high 
  area; 
  fine 
  equal 
  bifurcating 
  striae; 
  

  

  extremely 
  fine 
  concentric 
  striae; 
  punctate 
  

  

  interspaces. 
  

  

  Found 
  in 
  the 
  talus 
  of 
  Rochester 
  shale 
  above 
  Lew'iston 
  hights. 
  

  

  Rare. 
  Also 
  in 
  the 
  shale 
  at 
  Lockport 
  (Hall). 
  

  

  Genus 
  orthostrophia 
  Hall 
  

  

  [Ety.: 
  the 
  name 
  refers 
  to 
  the 
  relations 
  of 
  the 
  genus 
  to 
  Orthis 
  

   and 
  Stropheodonta] 
  

  

  (1883. 
  A". 
  Y. 
  state 
  geol. 
  2d 
  an. 
  rep't, 
  pi. 
  36; 
  1892. 
  Pal. 
  N. 
  Y. 
  

   v. 
  8, 
  pt 
  I, 
  p. 
  199, 
  222,, 
  253) 
  

  

  Shehs 
  with 
  convexity 
  of 
  valves 
  reversed; 
  surface 
  finely 
  plicated; 
  

   deep 
  narrow 
  muscular 
  area; 
  cardinal 
  process 
  elongate 
  and 
  simple. 
  

  

  Fig. 
  95 
  Orthis 
  (?) 
  punctostriata 
  

   with 
  enlargement 
  of 
  surface 
  

  

  