﻿The 
  Facjna 
  of 
  the 
  Niagara 
  Group. 
  109 
  

  

  This 
  is 
  undoubtedly 
  the 
  species 
  indicated 
  by 
  Dr. 
  Rominger 
  

   as 
  F. 
  spongilla, 
  but 
  at 
  the 
  time 
  of 
  printing 
  the 
  explanations 
  

   of 
  plates 
  for 
  the 
  Documentary 
  Edition 
  of 
  this 
  Report, 
  his 
  

   work 
  had 
  not 
  been 
  published. 
  

  

  Favosites 
  ^ 
  Forbesi 
  ;!yar. 
  occldentalis 
  n. 
  var. 
  

  

  Plate 
  4, 
  Figs. 
  6-15. 
  

  

  Favosites 
  Forbesi 
  ?. 
  Doc. 
  Edit. 
  28th 
  ,B 
  Rep. 
  St. 
  Mus. 
  Nat. 
  Hist. 
  Explanation 
  of 
  pi. 
  4, 
  

  

  figs. 
  6-15. 
  1876. 
  

   Compare 
  F. 
  Forbesi 
  Edwards 
  & 
  Haime. 
  British 
  Fossil 
  Corals, 
  p. 
  258, 
  pi. 
  60. 
  

  

  Corallum 
  hemispheric, 
  subglobose 
  or 
  pyriform; 
  calyces 
  very 
  

   unequal 
  in 
  size, 
  the 
  larger 
  ones 
  often 
  subcircular 
  and 
  about 
  

   three 
  mm. 
  in 
  diameter, 
  while 
  the 
  smallest 
  cells 
  are 
  often 
  not 
  

   more 
  than 
  one 
  mm. 
  at 
  their 
  apertures. 
  In 
  rare 
  specimens 
  the 
  

   diameter 
  of 
  the 
  larger 
  calyces 
  does 
  not 
  exceed 
  two 
  millimetres. 
  

   A 
  vertical 
  section 
  shows 
  the 
  walls 
  to 
  be 
  of 
  medium 
  thickness, 
  

   while 
  in 
  the 
  calyces 
  they 
  appear 
  strong 
  and 
  are 
  often 
  crenu- 
  

   late 
  from 
  the 
  longitudinal 
  strise. 
  Mural 
  pores, 
  situated 
  near 
  

   the 
  angles, 
  in 
  one 
  or 
  two 
  ranges, 
  depending 
  on 
  the 
  size 
  of 
  the 
  

   cell. 
  Cell-wall 
  granulose, 
  the 
  granulse 
  arranged 
  in 
  transverse 
  

   lines. 
  

  

  The 
  form 
  and 
  dimensions 
  of 
  the 
  coral 
  are 
  fairly 
  represented 
  

   in 
  the 
  figures 
  on 
  plate 
  4, 
  and 
  few 
  larger 
  specimens 
  have 
  been 
  

   observed 
  than 
  the 
  one 
  illustrated 
  in 
  figure 
  10. 
  The 
  species 
  is 
  

   very 
  abundant, 
  occurring 
  in 
  great 
  numbers 
  in 
  the 
  shaly 
  lime- 
  

   stone 
  deposits 
  of 
  Waldron 
  and 
  vicinity. 
  In 
  many 
  of 
  the 
  spec- 
  

   imens 
  the 
  epitheca 
  is 
  extended 
  from 
  the 
  base 
  over 
  the 
  sides 
  of 
  

   the 
  coral, 
  covering 
  the 
  cell-apertures, 
  and 
  not 
  unfrequently 
  

   some 
  of 
  the 
  larger 
  cells 
  upon 
  the 
  upper 
  face 
  of 
  the 
  coral 
  are 
  

   partially 
  closed 
  by 
  an 
  individual 
  epithecal 
  covering, 
  which 
  

   growing 
  inward 
  from 
  the 
  margins 
  finally 
  closes 
  the 
  aperture, 
  

   after 
  the 
  manner 
  of 
  an 
  operculum 
  with 
  a 
  central 
  node. 
  In 
  

   some 
  examples 
  this 
  epithecal 
  growth 
  begins 
  within 
  the 
  calyx 
  

   walls, 
  presenting 
  a 
  distinct 
  ring 
  with 
  a 
  central 
  circular 
  open- 
  

   ing, 
  giving 
  the 
  appearance 
  of 
  budding 
  from 
  the 
  parent 
  cell, 
  

   but 
  in 
  the 
  progress 
  of 
  growth 
  the 
  space 
  betwen 
  the 
  cell- 
  walls 
  

   and 
  the 
  epithecal 
  ring 
  is 
  closed 
  and 
  the 
  central 
  opening 
  be- 
  

   comes 
  in 
  like 
  manner 
  filled. 
  

  

  This 
  species 
  has 
  been 
  identified 
  with 
  F. 
  Forbesi, 
  chiefly 
  

   from 
  its 
  similarity 
  with 
  the 
  young 
  of 
  that 
  species, 
  as 
  repre- 
  

   sented 
  by 
  Edwards 
  & 
  Haime, 
  British 
  Fossil 
  Corals, 
  plate 
  60, 
  

   though 
  our 
  specimens 
  very 
  rarely 
  assume 
  the 
  form 
  there 
  illus- 
  

   trated, 
  which 
  is 
  similar 
  to 
  one 
  figured 
  by 
  Dr. 
  F. 
  Roemer, 
  

   from 
  the 
  Silurian 
  of 
  West 
  Tennessee. 
  We 
  have 
  no 
  specimens 
  

  

  