﻿70 
  Scientific 
  Intelligence. 
  

  

  and 
  a 
  general 
  resume 
  states 
  the 
  best 
  uses 
  to 
  which 
  the 
  various 
  

   stones 
  may 
  be 
  put. 
  The 
  volume 
  shows 
  a 
  large 
  amount 
  of 
  very- 
  

   careful 
  work 
  and 
  is 
  of 
  much 
  more 
  than 
  local 
  interest 
  and 
  value. 
  

  

  l. 
  v. 
  p. 
  

  

  8. 
  TJie 
  Cretaceous 
  Formations 
  of 
  the 
  Black 
  Hills 
  as 
  indicated 
  

   by 
  the 
  Fossil 
  Plants 
  ; 
  by 
  Lester 
  F. 
  Ward, 
  with 
  the 
  collabora- 
  

   tion 
  of 
  Walter 
  P. 
  Jenney, 
  Wm. 
  M. 
  Fontaine, 
  and 
  F. 
  H. 
  Knowl- 
  

   ton 
  (19th 
  Annual 
  Report 
  of 
  the 
  United 
  States 
  Geological 
  Survey, 
  

   Pt. 
  II, 
  pp. 
  521-958, 
  Plates 
  lvii-clxxii, 
  and 
  3 
  sketch 
  maps 
  in 
  

   text. 
  Washington, 
  1899). 
  — 
  The 
  foregoing 
  paper 
  is 
  especially 
  

   marked 
  by 
  a 
  completeness 
  of 
  description 
  and 
  illustration, 
  and 
  a 
  

   fulness 
  of 
  detail 
  concerning 
  the 
  localities 
  from 
  which 
  plants 
  were 
  

   obtained, 
  that 
  will 
  materially 
  lighten 
  the 
  labor 
  of 
  future 
  students 
  

   in 
  this 
  interesting 
  field. 
  It 
  is 
  a 
  very 
  important 
  contribution 
  to 
  

   American 
  paleobotany. 
  

  

  In 
  the 
  joint 
  work, 
  the 
  determination 
  of 
  Araucarioxylon 
  Hop- 
  

   pertonce 
  as 
  one 
  of 
  the 
  species 
  in 
  the 
  great 
  fossil 
  forests 
  of 
  conifers 
  

   occurring 
  in 
  the 
  main 
  cycad 
  horizon 
  is 
  by 
  Mr. 
  Knowlton. 
  The 
  

   identification 
  of 
  plants 
  irom 
  the 
  Hay 
  Creek, 
  Wyoming, 
  coal 
  field 
  

   is 
  by 
  Mr. 
  Fontaine. 
  A 
  number 
  of 
  new 
  species 
  are 
  described, 
  but 
  

   of 
  much 
  more 
  importance 
  is 
  the 
  recognition 
  of 
  some 
  twenty-five 
  

   forms 
  also 
  represented 
  in 
  the 
  so-called 
  Lower 
  Cretaceous 
  of 
  Vir- 
  

   ginia 
  and 
  Maryland, 
  particularly 
  in 
  the 
  Rappahannock 
  and 
  

   Mount 
  Vernon 
  series 
  of 
  Virginia, 
  and 
  the 
  Aquia 
  Creek 
  series 
  of 
  

   Virginia 
  and 
  Maryland. 
  The 
  contribution 
  by 
  Mr. 
  Jenney 
  deala 
  

   with 
  the 
  geology 
  of 
  the 
  Hay 
  Creek 
  coal 
  field, 
  which 
  has 
  evidently 
  

   been 
  worked 
  out 
  with 
  much 
  care. 
  The 
  remainder 
  of 
  the 
  work, 
  

   including 
  the 
  determination 
  of 
  plants 
  from 
  the 
  Dakota 
  group 
  

   proper 
  and 
  the 
  description 
  of 
  twenty-one 
  new 
  species 
  of 
  cycadean 
  

   trunks, 
  is 
  by 
  Mr. 
  Ward. 
  

  

  From 
  a 
  morphological 
  standpoint 
  the 
  greatest 
  interest 
  centers 
  

   in 
  the 
  Cycads. 
  The 
  descriptions 
  of 
  these, 
  accompanied 
  by 
  numer- 
  

   ous 
  plates, 
  show 
  at 
  once 
  the 
  wealth 
  and 
  beauty 
  of 
  the 
  cycadean 
  

   flora 
  of 
  the 
  Black 
  Hills. 
  In 
  both 
  the 
  number 
  of 
  species 
  and 
  the 
  

   completeness 
  of 
  their 
  preservation 
  this 
  locality 
  exceeds 
  any 
  

   hitherto 
  reported. 
  . 
  Bearing 
  in 
  mind 
  the 
  fact 
  that 
  cycadean 
  

   trunks, 
  although 
  long 
  known 
  from 
  various 
  European 
  Jurassic 
  

   and 
  Lower 
  Cretaceous 
  horizons, 
  have 
  been 
  among 
  the 
  rarest 
  of 
  

   fossil 
  plants, 
  these 
  new 
  forms 
  are 
  of 
  much 
  importance. 
  There 
  i& 
  

   just 
  cause 
  for 
  congratulation 
  that, 
  with 
  the 
  trunks 
  procured 
  from 
  

   the 
  Potomac 
  formation 
  of 
  Maryland, 
  it 
  has 
  become 
  possible 
  to 
  fill 
  

   up 
  many 
  of 
  the 
  gaps 
  in 
  our 
  knowledge 
  of 
  the 
  distribution 
  and 
  

   structure 
  of 
  this 
  interesting 
  group 
  of 
  Mesozoic 
  plants. 
  

  

  In 
  describing 
  these 
  Cycads 
  Professor 
  Ward 
  has 
  referred 
  them 
  all 
  

   to 
  the 
  genus 
  Gycadeoidea 
  of 
  Buckland, 
  in 
  this 
  respect 
  not 
  agree- 
  

   ing 
  with 
  most 
  English 
  and 
  continental 
  botanists. 
  

  

  The 
  principal 
  results 
  of 
  these 
  several 
  studies 
  are 
  discussed 
  and 
  

   given 
  in 
  convenient 
  tabular 
  form 
  at 
  the 
  close. 
  It 
  is 
  decided 
  that 
  

   in 
  the 
  Black 
  Hills 
  rim 
  below 
  the 
  Fort 
  Benton 
  there 
  is 
  a 
  probable 
  

   equivalent, 
  at 
  least 
  in 
  part, 
  of 
  the 
  Dakota 
  of 
  Kansas 
  and 
  Nebraska 
  

  

  