﻿Fur 
  

  

  NIAGARA 
  FALLS 
  AND 
  VICINITY 
  1 
  87 
  

  

  Orthostrophia 
  ( 
  ?) 
  fasciata 
  Hall 
  (Fig. 
  96). 
  Orthis 
  fasciata 
  

   Hall 
  (1852. 
  Pal 
  N. 
  Y. 
  2:255, 
  pi. 
  52) 
  

  

  Distinguishing 
  characters. 
  Semi- 
  

   oval 
  contour; 
  produced 
  hinge 
  

   line; 
  clustered 
  or 
  fasciculated 
  

   striae 
  almost 
  simple 
  at 
  their 
  origin, 
  

  

  , 
  . 
  . 
  , 
  . 
  1 
  , 
  . 
  Fig. 
  96 
  Orthostrophia 
  (?) 
  fasciata 
  

  

  diviamg 
  toward 
  the 
  margm. 
  

  

  Found 
  in 
  the 
  lower 
  Rochester 
  shale 
  at 
  Niagara 
  (?). 
  Also 
  at 
  

   Lockport 
  (Hall). 
  

  

  Genus 
  dalmanella 
  Hall 
  & 
  Clarke 
  

  

  [Ety. 
  : 
  proper 
  name] 
  

  

  (1892. 
  Pal. 
  N. 
  Y. 
  v. 
  8, 
  pt 
  I, 
  p. 
  205, 
  223) 
  

  

  Shells 
  plano-convex 
  or 
  subequally 
  biconvex 
  ; 
  pedicle 
  valve 
  usually 
  

   the 
  deeper, 
  often 
  elevated 
  at 
  the 
  umbo 
  and 
  arched 
  over 
  the 
  cardinal 
  

   area; 
  hinge 
  line 
  generally 
  shorter 
  than 
  the 
  greatest 
  width 
  of 
  the 
  

   shell 
  ; 
  surface 
  finely 
  striate. 
  Prominent 
  teeth 
  supported 
  by 
  lamellae 
  

   which 
  circumscribe 
  the 
  muscular 
  area; 
  cardinal 
  process 
  tri- 
  to 
  

   quadrilobed, 
  continued 
  downward 
  in 
  a 
  median 
  ridge 
  dividing 
  a 
  

   quadriplicate 
  muscular 
  area. 
  

  

  Dalmanella 
  elegantula 
  (Dalman) 
  (Fig. 
  97). 
  Orthis 
  elegan- 
  

   tula 
  Dalman 
  (Hall 
  1852. 
  Pal. 
  N. 
  Y. 
  2:2^2, 
  pi. 
  52, 
  fig. 
  3a-r) 
  

   ^'. 
  V^ 
  -'**' 
  Distinguishing 
  characters. 
  Strongly 
  con- 
  

  

  1^-. 
  i 
  ^y 
  ., 
  vex 
  pedicle 
  valve 
  with 
  high 
  but 
  narrow 
  area 
  

  

  ^JJI^^^^H^ 
  and 
  incurved 
  beak; 
  nearly 
  flat 
  brachial 
  valve; 
  

   -^^pi^ 
  generally 
  with 
  a 
  longitudinal 
  concavity 
  in 
  

  

  ^^^w 
  ^'j^s^ 
  -^ 
  -(-j^e 
  center; 
  fine 
  close 
  set 
  striae, 
  which 
  divide 
  

  

  ^^B- 
  / 
  dichotomously 
  toward 
  the 
  margin; 
  ex- 
  

  

  tremely 
  fine 
  concentric 
  lines 
  and 
  coarser 
  

  

  Fig. 
  97 
  Dalmanella 
  elegantula 
  . 
  i 
  i 
  • 
  

  

  growth 
  lines. 
  

   Found 
  in 
  the 
  Clinton 
  lenses, 
  and 
  abundantly 
  at 
  intervals 
  in 
  the 
  

   lower 
  and 
  middle 
  (Bryozoa 
  beds) 
  Rochester 
  shales 
  at 
  Niagara. 
  

   Also 
  at 
  Lockport 
  and 
  elsewhere 
  (Hall). 
  

  

  