﻿lOO 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  entirely 
  inclosed 
  by 
  the 
  limestone, 
  from 
  which 
  they 
  are 
  differen- 
  

   tiated 
  by 
  their 
  structureless 
  character. 
  The 
  lenses 
  exposed 
  on 
  the 
  

   Rome, 
  Watertown 
  and 
  Ogdensburg 
  road 
  are 
  rich 
  in 
  shells 
  of 
  

   orthoceratites 
  and 
  shields 
  of 
  trilobites 
  (Illaenus 
  ioxus), 
  

   while 
  the 
  lens 
  in 
  the 
  gorge 
  yields 
  chiefly 
  brachiopods, 
  the 
  most 
  

   abundant 
  of 
  which 
  are 
  the 
  smooth 
  Whitfieldellas, 
  the 
  small 
  W. 
  

   n 
  i 
  t 
  i 
  d 
  a 
  and 
  the 
  larger 
  W. 
  o 
  b 
  1 
  a 
  t 
  a 
  being 
  the 
  most 
  common. 
  

  

  The 
  following 
  species 
  have 
  been 
  obtained 
  from 
  the 
  lens 
  in 
  the 
  

   gorge: 
  

  

  Brachiopoda 
  

  

  I 
  Whitfieldella 
  nitida 
  abundant 
  

  

  2W. 
  nitidaoblata 
  abundant 
  

  

  3 
  W. 
  intermedia 
  common 
  

  

  4Atrypa 
  reticularis; 
  specimens 
  with 
  strong, 
  rounded 
  

  

  bifurcating 
  striae, 
  noded 
  at 
  intervals 
  by 
  strong 
  concentric 
  

  

  striae, 
  and 
  apparently 
  intermediate 
  between 
  the 
  typical 
  form 
  

  

  of 
  the 
  species 
  as 
  it 
  occurs 
  in 
  the 
  Clinton 
  and 
  upper 
  Hme- 
  

  

  stone 
  and 
  A. 
  nodostriata, 
  the 
  most 
  abundant 
  form 
  

  

  of 
  the 
  Rochester 
  shales. 
  

  

  5 
  Atrypa 
  nodostriata; 
  rather 
  common, 
  convex 
  and 
  

  

  more 
  elongate 
  than 
  in 
  the 
  shale 
  above, 
  with 
  the 
  plications 
  

   generally 
  sharper 
  and 
  bifurcating 
  near 
  the 
  front. 
  The 
  

   pedicle 
  valve 
  has 
  a 
  distinct 
  sinus 
  bordered 
  by 
  strong 
  plica- 
  

   tions, 
  the 
  corresponding 
  fold 
  being 
  marked 
  merely 
  by 
  

   strong 
  plications. 
  Anterior 
  margin 
  distinctly 
  sinuate. 
  The 
  

   nodulations 
  are 
  not 
  well 
  preserved 
  except 
  in 
  specimens 
  from 
  

   the 
  shaly 
  portions. 
  

  

  6 
  Atrypa 
  rugosa; 
  several 
  small 
  specimens, 
  both 
  valves 
  

  

  very 
  convex, 
  with 
  strongly 
  defined 
  sinus 
  in 
  pedicle 
  valve, 
  in 
  

   the 
  center 
  of 
  which 
  is 
  a 
  small 
  pHcation. 
  Plications 
  bifur- 
  

   cate 
  and 
  also 
  increase 
  by 
  intercalation; 
  crossed 
  by 
  strong 
  

   rugose 
  lines. 
  

  

  7 
  Rhynchotreta 
  cuneata 
  americana 
  rare 
  

  

  8 
  Camarotoechia 
  neglecta 
  rare 
  

  

  9 
  Anastrophia 
  interplicata 
  rare 
  

   10 
  Spirifer 
  niagarensis; 
  common, 
  large 
  and 
  robust,, 
  

  

  with 
  long 
  hinge 
  line 
  and 
  moderately 
  high 
  area, 
  and 
  strongly 
  

   incurved 
  beak. 
  The 
  sinus 
  is 
  flanked 
  by 
  two 
  stronger 
  plica- 
  

   tions 
  and 
  extends 
  to 
  the 
  beak. 
  The 
  plications 
  are 
  flattened 
  

   on 
  top. 
  

  

  