﻿FIFTH 
  REPORT 
  OF 
  THE 
  DIRECTOR 
  I908 
  201 
  

  

  are 
  the 
  separate 
  joints 
  of 
  this 
  form 
  fill 
  the 
  otherwise 
  fine 
  grained 
  

   limestone 
  containing 
  the 
  type 
  specimens. 
  It 
  is 
  therefore 
  obvious 
  

   that 
  accumulations 
  of 
  these 
  joints 
  are 
  competent 
  to 
  form 
  a 
  pecu- 
  

   h'arly 
  granular 
  limestone 
  that 
  may 
  at 
  times 
  appear 
  to 
  be 
  made 
  up 
  of 
  

   comminuted 
  crinoidal 
  fragments 
  and 
  again 
  as 
  of 
  undistinctly 
  

   oolitic 
  structure. 
  The 
  writer 
  has 
  collected 
  a 
  specimen 
  of 
  limestone 
  

   at 
  Glens 
  Falls 
  that 
  entirely 
  consists 
  of 
  just 
  such 
  granules 
  which 
  in 
  

   a 
  few 
  places 
  still 
  retain 
  their 
  original 
  serial 
  arrangement 
  and 
  which, 
  

   in 
  spite 
  of 
  the 
  obscuration 
  of 
  their 
  structure 
  by 
  secondary 
  processes, 
  

   quite 
  certainly 
  are 
  derived 
  from 
  calcareous 
  algae. 
  Stolley 
  has 
  al- 
  

   ready 
  pointed 
  out 
  that 
  the 
  Siphoneae 
  attained 
  not 
  only 
  a 
  high 
  

   development 
  in 
  Siluric 
  time 
  but 
  that 
  they 
  also 
  grew^ 
  in 
  great 
  abund- 
  

   ance 
  and 
  that 
  they 
  will 
  be 
  found 
  to 
  have 
  formed 
  many 
  limestones 
  

   in 
  that 
  era. 
  If 
  Solenopora 
  is 
  a 
  Coralline 
  alga, 
  then 
  also 
  that 
  family 
  

   of 
  algae 
  must 
  have 
  contributed 
  largely 
  to 
  the 
  formation 
  of 
  our 
  

   Trenton 
  limestone 
  by 
  the 
  var. 
  trentonensis 
  of 
  Solenop- 
  

   oracom 
  pacta. 
  

  

  Callithamnopsis 
  AMiitfield 
  

  

  Professor 
  Whitfield 
  has 
  proposed 
  this 
  new 
  genus 
  of 
  fossil 
  algae 
  

   for 
  a 
  form 
  before 
  described 
  by 
  Professor 
  Hall 
  as 
  Oldhamia 
  

   fruticosa 
  from 
  the 
  Trenton 
  limestone 
  of 
  Platteville, 
  Wis. 
  We 
  

   have 
  before 
  us 
  a 
  new 
  species 
  from 
  the 
  Trenton 
  of 
  New 
  York 
  

   referable 
  to 
  this 
  genus 
  and 
  will 
  for 
  this 
  reason 
  enter 
  a 
  little 
  more 
  

   fully 
  on 
  the 
  discussion 
  of 
  the 
  structure 
  of 
  the 
  better 
  preserved 
  

   genotype, 
  C. 
  fruticosa. 
  We 
  insert 
  here 
  copies 
  of 
  some 
  of 
  

   the 
  original 
  figures 
  [text 
  fig. 
  4-7] 
  illustrating 
  this 
  type 
  and 
  also 
  a 
  

   camera 
  drawing 
  [pi. 
  i, 
  fig. 
  3] 
  of 
  ours 
  of 
  one 
  of 
  the 
  types 
  to 
  show 
  

   more 
  clearly 
  some 
  of 
  the 
  important 
  features 
  of 
  the 
  form. 
  

  

  The 
  concise 
  original 
  diagnosis 
  of 
  the 
  genus 
  is 
  : 
  " 
  Frond 
  artic- 
  

   ulate, 
  branched, 
  branches 
  opposite 
  in 
  pairs, 
  in 
  whorls 
  near 
  the 
  

   upper 
  end 
  of 
  the 
  joints, 
  and 
  composed 
  of 
  single 
  joints 
  between 
  

   bifurcations." 
  

  

  The 
  camera 
  drawing 
  of 
  the 
  type 
  specimen 
  here 
  reproduced 
  

   shows 
  the 
  following 
  characters: 
  A 
  distinctly 
  monopodial 
  growth 
  

   of 
  the 
  thallus 
  with 
  a 
  thick 
  branch 
  of 
  uniform 
  thickness. 
  This 
  re- 
  

   tains 
  in 
  some 
  parts 
  a 
  thick 
  carbonaceous 
  test. 
  Where 
  the 
  latter 
  is 
  

   broken 
  out, 
  a 
  distinct 
  sharp 
  median 
  longitudinal 
  line 
  is 
  seen 
  on 
  the 
  

   impression 
  dividing 
  the 
  latter 
  into 
  two 
  convex 
  halves, 
  the 
  whole 
  

   giving 
  the 
  impression 
  of 
  being 
  produced 
  by 
  the 
  crushing 
  of 
  a 
  

   hollow 
  stem. 
  The 
  apex 
  of 
  the 
  branch 
  is 
  seen 
  to 
  be 
  rounded 
  and 
  

   sharply 
  defined. 
  In 
  several 
  parts 
  of 
  the 
  main 
  branch 
  distinct 
  

  

  