﻿NIAGARA 
  FALLS 
  AND 
  VICINITY 
  135 
  

  

  This 
  coralline 
  is 
  generally 
  very 
  massive 
  and 
  may 
  attain 
  a 
  diameter 
  

   of 
  2 
  feet. 
  Probably 
  includes 
  a 
  number 
  of 
  distinct 
  species. 
  

  

  

  .Mi 
  

  

  Fig. 
  28 
  Stromatopora 
  concentrica 
  Hall 
  with 
  an 
  enlargement 
  of 
  a 
  oross-sectlon 
  

  

  Found 
  at 
  Niagara 
  in 
  the 
  Lockport 
  limestone, 
  particularly 
  the 
  

   geodiferous 
  beds, 
  and 
  generally 
  common 
  throughout 
  the 
  middle 
  

   limestones. 
  Also 
  at 
  Lockport 
  and 
  elsewhere. 
  

  

  Class 
  ANTHOZOA 
  Ehrenberg 
  

  

  The 
  Anthozoa, 
  or 
  coral 
  polyps, 
  are 
  marine 
  animals 
  ranging 
  from 
  

   low 
  water 
  to 
  300 
  and 
  sometimes 
  even 
  1500 
  fathoms 
  (Zittel). 
  The 
  

   reef-building 
  types 
  however 
  do 
  not 
  flourish 
  in 
  depths 
  greater 
  than 
  

   50 
  fathoms, 
  and 
  are 
  generally 
  restricted 
  to 
  20 
  fathoms 
  or 
  less. 
  

   Both 
  simple 
  and 
  colonial 
  forms 
  occur, 
  the 
  latter 
  predominating 
  at 
  

   the 
  present 
  time, 
  while 
  the 
  former 
  were 
  abundant 
  in 
  the 
  Paleozoic. 
  

   The 
  two 
  important 
  types 
  of 
  Paleozoic 
  corals 
  are 
  the 
  "rugose 
  corals" 
  

   or 
  Tetracoralla, 
  and 
  the 
  tabulate 
  corals, 
  the 
  former 
  generally 
  simple, 
  

   the 
  latter 
  colonial 
  types.^ 
  

  

  The 
  simple 
  rugose 
  corallum 
  is 
  well 
  represented 
  by 
  Entero- 
  

   lasma. 
  It 
  consists 
  of 
  numerous 
  radiating 
  sepia, 
  disposed 
  in 
  

   several 
  cycles, 
  and 
  united 
  round 
  their 
  outer 
  margins 
  by 
  a 
  wall 
  or 
  

   tkcca 
  (pseudotheca). 
  This 
  is 
  formed 
  by 
  the 
  lateral 
  expansion 
  or 
  

   thickening 
  of 
  the 
  septa 
  in 
  that 
  region. 
  The 
  exothecal 
  prolongations 
  

   of 
  the 
  septa 
  are 
  visible 
  on 
  the 
  exterior 
  of 
  the 
  corrallum 
  as 
  costae, 
  

   which 
  are 
  frequently 
  represented 
  by 
  grooves 
  instead 
  of 
  ridges. 
  

   These, 
  in 
  the 
  genus 
  referred 
  to, 
  as 
  well 
  as 
  in 
  others, 
  commonly 
  

   show 
  the 
  peculiar 
  tetrameral 
  arrangement 
  characteristic 
  of 
  the 
  septa 
  

   of 
  this 
  group. 
  On 
  or 
  near 
  the 
  convex 
  longitudinal 
  surface 
  of 
  the 
  

   corallum 
  a 
  median, 
  or 
  " 
  cardinal 
  ", 
  septum 
  appears, 
  from 
  which 
  the 
  

  

  ^As 
  no 
  true 
  Hexacoralla 
  occur 
  in 
  the 
  formations 
  treated 
  of 
  in 
  these 
  

   pages, 
  an 
  account 
  of 
  their 
  structure 
  is 
  omitted. 
  

  

  