﻿NIAGARA 
  FALLS 
  AND 
  VICINITY 
  185 
  

  

  fined 
  radiating 
  striae, 
  which 
  curve 
  sHghtly 
  upward 
  on 
  the 
  lateral 
  

   margins 
  near 
  the 
  cardinal 
  area; 
  strongest 
  striae 
  reaching 
  to 
  beak; 
  

   increase 
  by 
  repeated 
  intercalation; 
  fine 
  concentric 
  striae. 
  

  

  Found 
  in 
  great 
  abundance 
  in 
  the 
  Manlius 
  limestone 
  of 
  North 
  

   Buffalo, 
  etc., 
  usually 
  in 
  the 
  condition 
  of 
  molds. 
  

  

  Genus 
  chonetes 
  Fischer 
  de 
  Waldheim 
  

  

  [Ety. 
  : 
  x«^>r/, 
  funnel] 
  

  

  (1837. 
  Oryctographic 
  dii 
  goiiv. 
  de 
  Moscozv, 
  pt 
  2, 
  p. 
  134; 
  1892. 
  

   Pal. 
  N. 
  Y. 
  V. 
  8, 
  pt 
  I, 
  p. 
  303) 
  

  

  Shells 
  concavo-convex 
  (in 
  our 
  species), 
  with 
  the 
  pedicle 
  valve 
  

   convex; 
  hinge 
  line 
  straig.ht, 
  making 
  the 
  greatest 
  diameter 
  of 
  the 
  

   shell; 
  areas 
  narrow; 
  the 
  triangular 
  opening 
  (delthyrium) 
  in 
  the 
  area 
  

   of 
  the 
  pedicle 
  valve 
  covered 
  by 
  a 
  convex 
  deltidium. 
  Upper 
  margin 
  

   of 
  area 
  bears 
  a 
  single 
  row 
  of 
  hollow 
  spines. 
  Area 
  of 
  brachial 
  valve 
  

   without 
  spines; 
  cardinal 
  process 
  appearing 
  quadrilobate. 
  Interior 
  

   of 
  shell 
  strongly 
  papillose 
  in 
  the 
  pallial 
  region. 
  A 
  low 
  median 
  ridge 
  

   divides 
  the 
  muscular 
  area 
  of 
  the 
  pedicle 
  valve. 
  A 
  similar 
  ridge 
  oc- 
  

   curs 
  in 
  the 
  brachial 
  valve. 
  External 
  surface 
  usually 
  covered 
  by 
  

   radiating 
  striae. 
  

  

  Chonetes 
  cornutus 
  (Hall) 
  (Fig. 
  93) 
  (1852. 
  Pal. 
  N. 
  Y. 
  2:64, 
  

   pi. 
  21) 
  

  

  Distinguishing 
  characters. 
  Semi- 
  

   circular; 
  fine 
  equal 
  striae, 
  round, 
  

   straight 
  and 
  bifurcating 
  with 
  similar 
  

   interspaces 
  ; 
  three 
  cardinal 
  spines 
  on 
  ^^^^ 
  93 
  chonetes 
  comutus 
  natural 
  size 
  and 
  

   each 
  side 
  of 
  beak, 
  obliquely 
  diverg- 
  

   ing 
  below, 
  curving 
  inward 
  at 
  middle 
  and 
  upper 
  parts; 
  outer 
  one 
  

   longest. 
  

  

  Found 
  (doubtfully) 
  in 
  the 
  Lockport 
  limestone 
  at 
  Niagara. 
  

  

  Genus 
  orthis 
  Dalman 
  

  

  (sensu 
  strictu) 
  

   ([Ety.: 
  opdo^, 
  straight; 
  in 
  allusion 
  to 
  hinge 
  line] 
  

  

  (1828. 
  Kongl. 
  Svenska 
  Vet. 
  Akad. 
  Handl. 
  p. 
  93, 
  96. 
  Hall 
  & 
  

   Clarke 
  1892; 
  Pal. 
  N. 
  Y. 
  v. 
  8, 
  pt 
  i, 
  p. 
  192) 
  

  

  Shells 
  plano-convex 
  in 
  contour; 
  costae 
  strong, 
  sharp 
  and 
  com- 
  

   paratively 
  few, 
  rarely 
  if 
  ever 
  bifurcating; 
  cardinal 
  area 
  of 
  pedicle 
  

  

  