﻿NIAGARA 
  FALLS 
  AND 
  VICINITY 
  2iq 
  

  

  leperditia 
  scalaris 
  Jones 
  (Fig. 
  150) 
  (Grabau. 
  Geol. 
  soc. 
  Am. 
  Bid. 
  

   11:371, 
  pi. 
  22) 
  

  

  Distinguishing 
  characters. 
  Bean-shaped 
  outline; 
  straight 
  hinge 
  

   line 
  with 
  salient 
  angles; 
  uniformly 
  curved 
  basal 
  margin; 
  an- 
  

   terior 
  and 
  posterior 
  marginal 
  

  

  borders; 
  ocular 
  tubercle 
  about 
  

   a 
  third 
  the 
  length 
  of 
  the 
  shell 
  

   from 
  the 
  anterior 
  end; 
  strong, 
  

   elongated 
  fold 
  or 
  " 
  dorsal 
  

   hump 
  " 
  below 
  the 
  hinge 
  line, 
  in 
  

   the 
  posterior 
  half 
  of 
  the 
  left 
  

  

  valve. 
  ^^^- 
  ^^^ 
  Leperditia 
  scalaris 
  (enlarged) 
  

  

  Found 
  in 
  the 
  Manlius 
  limestone 
  of 
  North 
  Buffalo 
  and 
  elsewhere 
  

   in 
  Erie 
  county. 
  It 
  is 
  a 
  common 
  species. 
  

  

  

  Genus 
  bollia 
  Jones 
  & 
  HoU 
  

  

  [Ety. 
  : 
  Boll, 
  proper 
  name] 
  

  

  (1886. 
  An. 
  and 
  mag. 
  nat. 
  hist., 
  ser. 
  5, 
  17:360) 
  

  

  Valves 
  oblong, 
  with 
  rounded 
  and 
  nearly 
  equal 
  ends; 
  hinge 
  line 
  

   straight, 
  ventral 
  margin 
  curved; 
  surface 
  punctate 
  and 
  bearing 
  a 
  

   rudely 
  horseshoe-shaped 
  ridge, 
  w4th 
  a 
  central 
  depression 
  within, 
  and 
  

   without 
  a 
  semilunar 
  ridge 
  on 
  each 
  side 
  and 
  parallel 
  to 
  the 
  outer 
  

   margins 
  of 
  the 
  shell, 
  which 
  are 
  slightly 
  rimmed. 
  

  

  Bollia 
  symmetrica 
  (Hall) 
  (Fig. 
  151). 
  Beyrichia 
  sym- 
  

   metrica 
  Hall. 
  (1852. 
  Fa/. 
  A^. 
  F. 
  2:317, 
  pi. 
  67) 
  

  

  Distinguishing 
  characters. 
  Extremely 
  small 
  size; 
  thin 
  horseshoe 
  

   ridge, 
  dividing 
  shell 
  into 
  three 
  nearly 
  equal 
  parts; 
  ridges 
  and 
  inter- 
  

  

  ^ 
  ^ 
  spaces 
  about 
  equal; 
  outer 
  ridges 
  not 
  continued 
  

  

  ventrally. 
  

  

  Found 
  in 
  a 
  fragment 
  of 
  weathered 
  Rochester 
  

   shale, 
  on 
  the 
  talus 
  along 
  the 
  Rome, 
  Watertown 
  and 
  

   Fig. 
  151 
  Bollia 
  sym- 
  Ogdcnsburg 
  railroad 
  cut 
  above 
  Lewiston. 
  As- 
  

  

  metrica 
  natural 
  size 
  

  

  and 
  enlarged 
  sociatcd 
  with 
  the 
  ucxt. 
  (One 
  specimen 
  found 
  was 
  

  

  larger 
  than 
  the 
  normal, 
  and 
  the 
  horseshoe 
  curve 
  rather 
  thick 
  ven- 
  

   trally, 
  but 
  not 
  as 
  thick 
  as 
  in 
  B. 
  lata 
  of 
  the 
  Clinton 
  group. 
  This 
  

   appears 
  intermediate 
  between 
  the 
  two 
  species.) 
  Also 
  found 
  at 
  

   Lockport 
  (Hall). 
  

  

  f 
  

  

  