﻿NIAGARA 
  FALLS 
  AND 
  VICINITY 
  

  

  191 
  

  

  valves 
  in 
  some 
  specimens; 
  surface 
  marked 
  only 
  by 
  concentric 
  lines 
  

   of 
  growth, 
  which 
  are 
  strongest 
  in 
  old 
  shells. 
  

  

  Fig. 
  1C3 
  Pentamerus 
  oblongus 
  

  

  Found 
  in 
  the 
  upper 
  crystalline 
  Clinton 
  limestone 
  at 
  Niagara 
  

   (i 
  specimen). 
  The 
  species 
  is 
  characteristic 
  of 
  the 
  lower 
  Clinton 
  

   limestone, 
  east 
  of 
  Lockport. 
  

  

  Genus 
  barrandella 
  Hall 
  & 
  Clarke 
  

  

  [Ety.: 
  proper 
  name] 
  

  

  (Hall 
  & 
  Clarke. 
  1894. 
  Pal. 
  N. 
  Y. 
  v. 
  8, 
  pt 
  2, 
  p. 
  241, 
  243) 
  

  

  Small 
  pentameroid 
  shells, 
  of 
  a 
  galeate 
  form 
  or 
  helmet-shaped 
  con- 
  

   tour, 
  with 
  a 
  smooth, 
  or 
  rarely 
  plicated 
  surface. 
  A 
  spondylium 
  is 
  

   present, 
  but 
  is 
  not 
  supported 
  by 
  a 
  septum. 
  

  

  Barrandella 
  fcrnicata 
  (Hall) 
  (Fig. 
  104). 
  Pentamerus 
  

   f 
  o 
  r 
  n 
  i 
  c 
  a 
  t 
  u 
  s 
  Hall 
  {Pal 
  N. 
  Y. 
  2:81, 
  pi. 
  24) 
  

  

  Distinguishing 
  characters. 
  Helmet- 
  

   shaped 
  contour, 
  very 
  convex 
  pedicle 
  

   valve, 
  with 
  overarching 
  beak; 
  sur- 
  

   face 
  obscurely 
  plicate 
  longitudinally. 
  

   Found 
  in 
  the 
  upper 
  crystalline 
  

   Clinton 
  limestone 
  at 
  Niagara. 
  Also 
  in 
  the 
  same 
  limestone 
  at 
  

   Lockport 
  (Hall). 
  

  

  Fig. 
  104 
  Barrandella 
  fornicata 
  

  

  