﻿Report 
  of 
  the 
  State 
  Geologist. 
  843 
  

  

  Spirifer 
  mucronatus, 
  Conrad, 
  var. 
  posterus, 
  var. 
  nov. 
  

   (Plate 
  xxxiv, 
  figs. 
  27-31.) 
  

   A 
  late 
  variety 
  of 
  the 
  typical 
  Hamilton 
  form, 
  characterized 
  by 
  

   its 
  small 
  size, 
  usually 
  narrow 
  bodies 
  and 
  acuminate 
  cardinal 
  

   extremities. 
  

  

  Chemung 
  group. 
  Tompkins 
  county, 
  iJT. 
  Y, 
  

  

  Spirifer 
  disjunctus, 
  Soweebt, 
  var. 
  sulcifer, 
  var. 
  nov. 
  

   (Plate 
  xxx, 
  fig. 
  16.) 
  

   This 
  variety 
  is 
  distinguished 
  by 
  the 
  sharply 
  defined 
  median 
  

   sulcus 
  on 
  the 
  fold 
  of 
  the 
  brachial 
  valve. 
  It 
  has 
  heretofore 
  been 
  

   embraced 
  within 
  the 
  limits 
  of 
  S. 
  disjunctus, 
  but 
  the 
  character 
  

   referred 
  to 
  appears 
  to 
  be 
  persistent. 
  

   Chemung 
  group. 
  Near 
  Olean, 
  N. 
  Y. 
  

  

  Spirifer 
  Williamsi, 
  sp. 
  nov. 
  

   (Plate 
  xxxvii, 
  figs. 
  20, 
  21, 
  22.) 
  

  

  Shells 
  of 
  the 
  form 
  of 
  Spirifer 
  increbescens, 
  Hall, 
  and 
  varying 
  

   but 
  little 
  in 
  size. 
  Median 
  fold 
  and 
  sinus 
  well 
  developed. 
  The 
  

   latter 
  bearing 
  usually 
  three, 
  sometimes 
  four 
  plications, 
  finer 
  

   than 
  those 
  on 
  the 
  lateral 
  slopes. 
  Of 
  these 
  the 
  median 
  plication 
  

   is 
  generally 
  the 
  strongest. 
  This, 
  however, 
  is 
  not 
  always 
  the 
  

   case, 
  the 
  arrangement 
  of 
  these 
  plications 
  being 
  frequently 
  quite 
  

   irregular. 
  The 
  median 
  fold 
  generally 
  bears 
  a 
  median 
  groove 
  and 
  

   one 
  lateral 
  plication 
  on 
  each 
  side. 
  On 
  each 
  lateral 
  slope 
  of 
  the 
  

   shell 
  are 
  seven 
  or 
  eight 
  plications. 
  

  

  A 
  normal 
  example 
  measures 
  : 
  Length, 
  15 
  mm. 
  ; 
  width 
  on 
  

   hinge, 
  21 
  mm. 
  

  

  Chemung 
  group. 
  Allegany 
  county, 
  JY. 
  Y. 
  

  

  Spirifer 
  Newberryi, 
  Hall, 
  1883. 
  

  

  [See 
  Rept. 
  State 
  Geologist 
  for 
  18S2, 
  plate 
  (xxxi) 
  56, 
  figs. 
  9, 
  10.] 
  

   (Plate 
  xxxi, 
  figs. 
  9, 
  10.) 
  

   Shell 
  moderately 
  large, 
  with 
  sharp 
  cardinal 
  angles. 
  Surface 
  

   plication 
  consisting 
  of 
  numerous 
  fine 
  simple 
  or 
  duplicate 
  ribs 
  

   which 
  cover 
  the 
  median 
  fold. 
  On 
  each 
  lateral 
  slope 
  there 
  are 
  

   twenty-five 
  to 
  thirty 
  of 
  these 
  plications. 
  The 
  plications 
  and 
  the 
  

   grooves 
  between 
  them 
  are 
  covered 
  with 
  fine 
  radiating 
  lines. 
  

   Waverly 
  group. 
  Ohio. 
  

  

  