﻿C. 
  E. 
  Beecher 
  — 
  Uintacr 
  inns 
  from 
  Kansas. 
  267 
  

  

  Art. 
  XXVI. 
  — 
  On 
  a 
  large 
  slab 
  of 
  ZTintacr 
  inns 
  from 
  Kansas 
  / 
  

   by 
  C. 
  E. 
  Beecher. 
  With 
  Plates 
  III 
  and 
  IV. 
  

  

  A 
  large 
  slab 
  of 
  limestone 
  preserving 
  on 
  its 
  surface 
  numer- 
  

   ous 
  specimens 
  of 
  ZT'mtacrinus 
  socialis 
  Grinnell 
  has 
  recently 
  

   been 
  placed 
  in 
  the 
  exhibition 
  series 
  of 
  the 
  Yale 
  University 
  

   Museum. 
  This 
  slab 
  is 
  of 
  especial 
  interest 
  on 
  account 
  of 
  its 
  

   size 
  and 
  for 
  the 
  perfection 
  of 
  the 
  crinoids 
  represented. 
  Bather* 
  

   has 
  so 
  ably 
  described 
  this 
  species 
  that 
  nothing 
  of 
  consequence 
  

   can 
  be 
  added 
  regarding 
  the. 
  details 
  of 
  structure 
  and 
  probable 
  

   habits. 
  The 
  present 
  notice, 
  therefore, 
  will 
  necessarily 
  be 
  

   restricted 
  to 
  minor 
  features. 
  

  

  The 
  first 
  specimens 
  of 
  Uintacrintis 
  were 
  collected 
  by 
  

   Professor 
  Marsh 
  in 
  1870, 
  from 
  the 
  Cretaceous 
  of 
  the 
  Uintah 
  

   Mountains, 
  Utah. 
  Later, 
  in 
  1876, 
  better 
  examples 
  were 
  

   obtained 
  in 
  western 
  Kansas 
  by 
  Dr. 
  S. 
  W. 
  Williston 
  and 
  by 
  

   Professor 
  B. 
  F. 
  Mudge 
  for 
  the 
  Yale 
  Museum, 
  which 
  now 
  con- 
  

   tains 
  collections 
  of 
  this 
  crinoid 
  from 
  Trego, 
  Gore, 
  Logan, 
  and 
  

   Wallace 
  Counties, 
  Kansas. 
  Notwithstanding 
  this 
  considerable 
  

   geographic 
  range, 
  the 
  horizon 
  appears 
  to 
  be 
  nearly 
  constant 
  at 
  

   about 
  the 
  middle 
  of 
  the 
  Niobrara 
  Chalk. 
  

  

  The 
  specimens 
  are 
  uniformly 
  on 
  the 
  underside 
  of 
  thin 
  len- 
  

   ticular 
  plates 
  of 
  a 
  limestone 
  that 
  in 
  itself 
  is 
  an 
  encrinital 
  rock 
  

   composed 
  of 
  dissociated 
  crinoid 
  elements. 
  The 
  lenses 
  of 
  lime- 
  

   stone 
  seldom 
  have 
  a 
  maximum 
  thickness 
  of 
  an 
  inch. 
  Usually 
  

   the 
  calyces 
  of 
  Uintacrinns 
  are 
  almost 
  completely 
  flattened, 
  

   but 
  occasionally, 
  as 
  in 
  the 
  slab 
  here 
  described, 
  they 
  stand 
  out 
  

   in 
  considerable 
  relief, 
  though 
  in 
  none 
  is 
  the 
  normal 
  fullness 
  

   preserved. 
  

  

  The 
  slab 
  represented 
  on 
  Plate 
  III 
  measures 
  six 
  feet, 
  seven 
  

   inches, 
  in 
  length 
  (2 
  meters) 
  by 
  four 
  feet, 
  six 
  and 
  one-half 
  

   inches 
  in 
  breadth 
  (J 
  m 
  38 
  cm 
  ) 
  and, 
  after 
  making 
  allowance 
  for 
  

   irregularities 
  in 
  outline, 
  it 
  contains 
  about 
  twenty-seven 
  square 
  

   feet 
  of 
  surface 
  (25,800 
  sq 
  cm 
  ). 
  In 
  this 
  area 
  are 
  the 
  calyces 
  of 
  

   two 
  hundred 
  and 
  twenty 
  individuals 
  of 
  Uintacrinus 
  socialis. 
  

   The 
  diameter 
  of 
  a 
  calyx 
  of 
  average 
  size, 
  in 
  a 
  somewhat 
  flat- 
  

   tened 
  condition, 
  is 
  about 
  60 
  mm 
  . 
  Occasionally 
  a 
  specimen 
  

   measures 
  70 
  mm 
  across, 
  and 
  apparently 
  this 
  is 
  nearly 
  the 
  maxi- 
  

   mum 
  size 
  attained 
  by 
  the 
  species. 
  The 
  smallest 
  specimens 
  are 
  

   not 
  more 
  than 
  20 
  r 
  " 
  m 
  in 
  diameter. 
  The 
  arm-branches 
  can 
  

   seldom 
  be 
  traced 
  more 
  than 
  10 
  crn 
  from 
  the 
  calyx, 
  though 
  sepa- 
  

   rate 
  ones 
  extend 
  at 
  least 
  five 
  times 
  this 
  distance 
  over 
  the 
  sur- 
  

   face. 
  

  

  *On 
  Uintacrinus: 
  a 
  Morphological 
  Study. 
  By 
  F. 
  A. 
  Bather, 
  M. 
  A. 
  Proceed- 
  

   ings 
  of 
  the 
  Zoological 
  Society 
  of 
  London, 
  vol. 
  1895, 
  pp. 
  974-1004, 
  pis. 
  liv-lvi, 
  

   1896. 
  

  

  