﻿386 
  Scientific 
  Intelligence. 
  

  

  eye, 
  structureless, 
  dull, 
  uniform, 
  covering 
  that 
  invests 
  their 
  outer 
  

   surfaces 
  and 
  cuts 
  off 
  the 
  view 
  of 
  the 
  normal 
  organs 
  of 
  the 
  armor. 
  

   A 
  closer 
  examination 
  revealed 
  the 
  fact 
  that 
  this 
  was 
  not 
  an 
  

   occasional 
  condition 
  but 
  the 
  normal 
  state 
  of 
  these 
  cycads, 
  and 
  

   that 
  the 
  cases 
  in 
  which 
  this 
  outer 
  coating 
  is 
  wanting 
  represent 
  

   the 
  abnormal 
  state. 
  It 
  further 
  became 
  clear 
  that 
  there 
  really 
  are 
  

   no 
  cases 
  in 
  which 
  it 
  is 
  naturally 
  absent, 
  and 
  that 
  its 
  absence 
  is 
  

   always 
  due 
  to 
  some 
  external 
  influence 
  acting 
  upon 
  the 
  surface 
  

   which 
  has 
  removed 
  it. 
  * 
  * 
  * 
  * 
  

  

  " 
  The 
  special 
  susceptibility 
  to 
  petrifaction 
  on 
  the 
  part 
  of 
  the 
  

   ramentum 
  explains 
  the 
  presence 
  of 
  the 
  external 
  covering 
  of 
  the 
  

   Wyoming 
  Jurassic 
  cycads, 
  since 
  it 
  seems 
  actually 
  to 
  consist 
  in 
  a 
  

   mass 
  of 
  these 
  ramentaceous 
  hairs, 
  which 
  in 
  some 
  way 
  developed 
  

   so 
  luxuriantly 
  upon 
  the 
  sides 
  of 
  the 
  petioles, 
  as 
  to 
  push 
  out 
  

   beyond 
  the 
  surface, 
  and 
  roll 
  over 
  the 
  spaces 
  formerly 
  occupied 
  

   by 
  the 
  leaves 
  and 
  fruits. 
  It 
  seems 
  necessary 
  to 
  assume 
  that 
  this 
  

   occurred 
  long 
  after 
  the 
  fall 
  of 
  the 
  leaves, 
  and, 
  indeed 
  this 
  latter 
  

   doubtless 
  took 
  place 
  much 
  as 
  it 
  does 
  in 
  living 
  cycads, 
  the 
  leaves 
  

   always 
  forming 
  a 
  crown 
  to 
  the 
  trunk 
  and 
  falling 
  away 
  as 
  the 
  

   trunk 
  elongates, 
  leaving 
  only 
  their 
  persistent 
  bases 
  to 
  form 
  a 
  

   false 
  bark. 
  These 
  are 
  not 
  wholly 
  dead, 
  but 
  manifest 
  vegetative 
  

   activity, 
  and 
  doubtless 
  have 
  some 
  physiological 
  function." 
  

  

  From 
  these 
  facts, 
  supported 
  by 
  sections 
  and 
  polished 
  surfaces, 
  

   it 
  is 
  decided, 
  that 
  " 
  Gycadella 
  developed 
  an 
  exuberant 
  growth 
  of 
  

   fine 
  scales 
  or 
  hairs 
  from 
  the 
  bases 
  of 
  its 
  old 
  petioles 
  below 
  the 
  

   apex, 
  which 
  formed 
  a 
  woolly 
  or 
  mossy 
  covering 
  of 
  considerable 
  

   thickness, 
  sufficient 
  when 
  tightly 
  appressed 
  to 
  the 
  trunk 
  and 
  

   petrified, 
  there 
  to 
  form 
  a 
  layer 
  5-1 
  5 
  mm 
  thick 
  all 
  over 
  the 
  fossil 
  

   trunks." 
  

  

  Whoever 
  has 
  seen 
  these 
  trunks 
  will 
  certainly 
  grant 
  from 
  the 
  

   briefest 
  observation 
  that 
  their 
  development 
  of 
  ramentum 
  was 
  

   very 
  profuse 
  ; 
  and 
  must 
  have 
  given 
  the 
  trunks 
  below 
  the 
  crown 
  

   of 
  leaves 
  the 
  appearance 
  seen 
  in 
  certain 
  Cacti. 
  Is 
  it 
  not 
  quite 
  

   possible 
  that 
  they 
  grew 
  in 
  dry, 
  cold, 
  or 
  semi-arid 
  situations 
  ? 
  

   This 
  would 
  account 
  at 
  least 
  in 
  part 
  for 
  their 
  small 
  size. 
  

  

  The 
  present 
  new 
  series 
  of 
  cycadaceous 
  plants 
  greatly 
  enhances 
  

   the 
  interest 
  and 
  value 
  of 
  the 
  recent 
  discovery 
  and 
  investigation 
  

   of 
  the 
  remains 
  of 
  the 
  extensive 
  cycadean 
  vegetation 
  occurring 
  in 
  

   strata 
  of 
  the 
  Black 
  Hills 
  rim 
  regarded 
  as 
  lowermost 
  Cretaceous 
  

   by 
  some 
  and 
  upper 
  Jurassic 
  by 
  others. 
  

  

  The 
  assigned 
  species 
  of 
  North 
  American 
  cycadean 
  trunks 
  now 
  

   numbers 
  52, 
  referred 
  to 
  two 
  genera 
  as 
  follows: 
  

  

  Upper 
  Jurassic 
  (?) 
  of 
  the 
  Black 
  Hills 
  (Dakota 
  and 
  Wyoming); 
  Cycadeoidea 
  daco- 
  

   tensis 
  Macbride, 
  colossalis, 
  Wellsii, 
  minnekahtensis, 
  pulcherrima, 
  cicatricula, 
  

   turrita, 
  Macbridei, 
  Marshiana, 
  furcata, 
  Colei, 
  Paynei, 
  aspera, 
  insolita, 
  occiden- 
  

   talism 
  Jenneyana, 
  ingens, 
  formosa, 
  Stilwelli, 
  excelsa, 
  nana, 
  and 
  Wielandi 
  (last 
  

   20 
  species 
  Ward). 
  

  

  Upper 
  Jurassic, 
  central 
  Wyoming, 
  — 
  Cycadella 
  Beecheriana, 
  Beedii, 
  Wyoming 
  ens 
  is, 
  

   Knoiultoniana, 
  compressa, 
  Jurassica, 
  nodosa, 
  cirrata, 
  exogena, 
  ramentosa, 
  fer- 
  

   ruginea, 
  contracta, 
  gravis, 
  verrucosa, 
  jejuna, 
  concinna, 
  crepidaria, 
  gelida, 
  car- 
  

   bonensis 
  and 
  Knightii 
  (all 
  Ward's 
  species). 
  

  

  