﻿208 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  transversely 
  elliptic 
  slightly 
  projecting 
  apertures 
  surrounded 
  by 
  a 
  

   thickened 
  rim 
  and 
  appear 
  to 
  alternate 
  on 
  opposite 
  sides 
  of 
  the 
  stem 
  

   and 
  branches. 
  

  

  There 
  are 
  no 
  traces 
  of 
  internal 
  walls 
  observable 
  in 
  the 
  badly 
  

   flattened 
  specimens. 
  

  

  While 
  it 
  is 
  perfectly 
  conceivable 
  that 
  all 
  the 
  apparent 
  apertures 
  

   could 
  be 
  but 
  the 
  former 
  places 
  of 
  attachment 
  of 
  lost 
  branches, 
  it 
  

   is 
  also 
  quite 
  as 
  sure 
  that 
  this 
  form, 
  found 
  in 
  another 
  association, 
  

   v^^ould 
  be 
  unhesitatingly 
  referred 
  to 
  the 
  graptolites 
  and 
  brought 
  

   into 
  the 
  neighborhood 
  of 
  Mastigograptus 
  where 
  it 
  closely 
  resembles 
  

   in 
  general 
  habit 
  and 
  structure 
  the 
  Utica 
  form, 
  M 
  . 
  a 
  r 
  u 
  n 
  d 
  i 
  - 
  

   naceus 
  (Hall). 
  

  

  As 
  in 
  the 
  case 
  of 
  Corematocladus 
  densa 
  the 
  car- 
  

   bonaceous 
  test 
  is 
  so 
  thick 
  and 
  so 
  glossy 
  that 
  it 
  is 
  more 
  suggestive 
  

   of 
  the 
  cliitinous 
  periderm 
  of 
  a 
  graptolite 
  than 
  of 
  the 
  cortex 
  of 
  an 
  

   alga 
  and 
  it 
  would 
  require 
  unmistakable 
  algal 
  characters 
  in 
  the 
  

   composition 
  of 
  the 
  branches 
  and 
  the 
  propagative 
  organs 
  to 
  war- 
  

   rant 
  a 
  reference 
  to 
  the 
  vegetable 
  kingdom. 
  

  

  Horizon 
  and 
  locality. 
  In 
  the 
  shaly 
  intercalation 
  of 
  the 
  lowest 
  

   limestone 
  beds 
  overlying 
  the 
  "Black 
  marble" 
  at 
  Glens 
  Falls, 
  

   N. 
  Y. 
  

  

  Concluding 
  Remarks 
  

  

  There 
  are 
  in 
  this 
  paper 
  more 
  fully 
  noted 
  three 
  species 
  of 
  fossils 
  

   from 
  the 
  Trenton 
  rocks 
  of 
  New 
  York 
  whose 
  position 
  among 
  the 
  

   m.arine 
  algae 
  seems 
  fairly 
  well 
  established. 
  These 
  are: 
  

  

  Primicorallina 
  trentonensis 
  Whitfield 
  Callithamnopsis 
  delicatula 
  sp. 
  nov. 
  

   Corematocladus 
  densa 
  sp. 
  nov. 
  

  

  The 
  first 
  named 
  is 
  a 
  calcareous 
  alga, 
  which 
  before 
  was 
  placed 
  

   among 
  the 
  Coralline 
  algae, 
  but 
  is 
  believed 
  by 
  the 
  writer 
  to 
  be 
  a 
  

   verticillate 
  Siphonea. 
  The 
  other 
  two 
  forms 
  possess 
  only 
  car- 
  

   bonaceous 
  tests 
  and 
  are 
  characterized 
  by 
  the 
  great 
  mass 
  of 
  thin 
  

   branchlets 
  borne 
  on 
  the 
  axial 
  stem. 
  In 
  C^^llithamnopsis 
  

   delicatula 
  these 
  branchlets 
  are 
  arranged 
  in 
  whorls, 
  in 
  the 
  

   other 
  form 
  they 
  are 
  irregularly 
  distributed 
  on 
  the 
  thick 
  axial 
  

   stem 
  and 
  frequently 
  bifurcate. 
  The 
  aspect 
  of 
  these 
  forms 
  is 
  that 
  

   of 
  Florideae 
  and 
  their 
  habitus, 
  which 
  alone 
  is 
  now 
  available, 
  per- 
  

   mits 
  of 
  comparison 
  with 
  several 
  families 
  of 
  that 
  class. 
  

  

  It 
  is 
  probable 
  that 
  calcareous 
  algae 
  have 
  played 
  an 
  important 
  

   role 
  in 
  the 
  formation 
  of 
  the 
  limestones 
  of 
  the 
  Trenton 
  formation. 
  

   This 
  is 
  not 
  only 
  suggested 
  by 
  the 
  frequency 
  of 
  the 
  small 
  joints 
  of 
  

   Primicorallina 
  in 
  the 
  rock 
  which 
  contains 
  the 
  types, 
  but 
  also 
  by 
  

   the 
  fact 
  that 
  there 
  occur 
  peculiarly 
  granular 
  and 
  oolitic 
  lime- 
  

  

  