﻿NIAGARA 
  FALLS 
  AND 
  VICINITY 
  

  

  171 
  

  

  non-celluliferous 
  side 
  oblong, 
  quadrangular, 
  rarely 
  oval; 
  branches 
  

   finely 
  striate. 
  

  

  Found 
  in 
  the 
  Bryozoa 
  bed 
  of 
  the 
  Rochester 
  shale 
  at 
  Niagara. 
  

   Also 
  in 
  the 
  same 
  rock 
  at 
  Lockport 
  and 
  elsewhere 
  (Hall). 
  

  

  Genus 
  semicoscinium 
  Prout 
  

   [Ety. 
  : 
  semi, 
  half 
  (somewhat 
  like); 
  ■/.6(Ty.rMj>, 
  sieve; 
  C 
  o 
  s 
  c 
  i 
  n 
  - 
  

   i 
  u 
  m 
  , 
  a 
  genus 
  of 
  Bryozoa] 
  

  

  (1859. 
  St 
  Louis 
  acad. 
  sci. 
  Trans, 
  i 
  443) 
  

  

  Zoarium 
  funnel-shaped, 
  celluliferous 
  on 
  the 
  outer 
  side; 
  dissepi- 
  

   ments 
  wide, 
  very 
  short, 
  the 
  branches 
  appearing 
  to 
  anastomose 
  on 
  the 
  

   non-poriferous 
  face, 
  where 
  the 
  fenestrules 
  are 
  subrhomboidal 
  or 
  

   rounded. 
  Apertures 
  in 
  two 
  rows, 
  with 
  a 
  very 
  high 
  median 
  keel, 
  

   which 
  is 
  expanded 
  at 
  the 
  summit. 
  

  

  Semicoscinium 
  tenuiceps 
  (Hall) 
  (Fig. 
  71, 
  y2). 
  Fenestella 
  

   tenuiceps 
  Hall 
  (1852. 
  Pal. 
  N. 
  Y. 
  2:165, 
  pl- 
  4oD, 
  fig. 
  2a-h) 
  

   Fenestella 
  prisca? 
  Hall 
  (1852. 
  Fal. 
  N. 
  Y. 
  2 
  :^o, 
  pi. 
  19, 
  

   fig. 
  4a-m) 
  

  

  Distinguishing 
  characters. 
  Carina 
  sharp 
  and 
  thin 
  ; 
  transverse 
  dis- 
  

   sepiments 
  not 
  extending 
  as 
  high 
  as 
  the 
  branches, 
  sometimes 
  scarcely 
  

  

  Fig. 
  71 
  Senfiicoscinlum 
  tenuiceps, 
  Clinton. 
  With 
  

   enlargements 
  

  

  Fig. 
  72 
  Semicoscinium 
  tenuiceps. 
  Niag- 
  

   ara. 
  Enlaraemenrs 
  of 
  celluliferous 
  and 
  

   non-celluliferous 
  faces 
  

  

  visible 
  ; 
  round 
  large 
  apertures 
  opening 
  laterally 
  so 
  as 
  to 
  be 
  scarcely 
  

   visible 
  when 
  looking 
  down 
  on 
  the 
  frond; 
  non-celluliferous 
  side 
  with 
  

   oval 
  fenestrules, 
  branches 
  on 
  non-celluliferous 
  side 
  striate, 
  appear- 
  

   ing 
  granular 
  when 
  worn. 
  

  

  Found 
  in 
  the 
  Bryozoa 
  beds 
  of 
  the 
  Rochester 
  shales 
  at 
  Niagara; 
  

   also 
  at 
  Lockport 
  (Hall) 
  (?). 
  It 
  also 
  occurs 
  in 
  the 
  Clinton 
  beds 
  at 
  

   Lockport, 
  and 
  probably 
  also 
  at 
  Niagara. 
  

  

  