﻿jiudgeJ 
  

  

  CRETACEOUS 
  DAKOTA. 
  293 
  

  

  parison 
  of 
  numerous 
  specimens 
  from 
  Greenland 
  and 
  Europe, 
  with 
  our 
  

   Dakota 
  and 
  the 
  living 
  Sassafras 
  officinale^ 
  we 
  obtain 
  the 
  following 
  con- 
  

   clusion 
  by 
  the 
  highest 
  authorities"^ 
  Prof. 
  W. 
  P. 
  Schimper 
  says, 
  "That 
  

   these 
  leaves, 
  very 
  variable 
  in 
  size, 
  present 
  such 
  a 
  remarkable 
  likeness 
  

   to 
  those 
  of 
  S. 
  officinale^ 
  now 
  living 
  in 
  oS^orth 
  America, 
  that 
  one 
  would 
  be 
  

   disposed 
  to 
  consider 
  them 
  as 
  belonging 
  to 
  an 
  homologous 
  species." 
  

   And 
  Lesquereux 
  adds, 
  " 
  Comparing 
  leaves 
  of 
  *S'. 
  officinale 
  with 
  those 
  

   represented 
  by 
  Count 
  Saporta, 
  in 
  the 
  Flora 
  of 
  Sezane, 
  and 
  the 
  specimens 
  

   of 
  >S'. 
  mudgei 
  from 
  Kansas, 
  it 
  is 
  impossible 
  for 
  me 
  to 
  recognize 
  any 
  char- 
  

   acter, 
  even 
  any 
  specific 
  difference 
  by 
  which 
  these 
  leaves 
  could 
  be 
  sep- 
  

   arated."* 
  This 
  extreme 
  persistence 
  (by 
  which 
  I 
  lose 
  my 
  namesake) 
  it 
  . 
  

   must 
  be 
  recollected 
  covers 
  a 
  period 
  of 
  one-eighth 
  of 
  the 
  earth's 
  geologi- 
  

   cal 
  history. 
  On 
  more 
  careful 
  study 
  of 
  these 
  fossil 
  leaves 
  it 
  is 
  most 
  

   probable 
  that 
  others 
  may 
  be 
  found 
  specifically 
  like 
  those 
  now 
  living. 
  

   The 
  fig, 
  in 
  its 
  nervation 
  and 
  especially 
  its 
  areolation, 
  is 
  of 
  the 
  same 
  

   character 
  as 
  many 
  species 
  now 
  living 
  in 
  Cuba 
  and 
  Florida.! 
  Had 
  these 
  

   leaves 
  been 
  found 
  in 
  Post-Pliocene 
  very 
  many 
  of 
  them 
  would 
  have 
  been 
  

   assigned 
  to 
  living 
  species. 
  The 
  persistence 
  of 
  vegetable 
  forms 
  has 
  

   been 
  more 
  strong, 
  through 
  all 
  geological 
  ages, 
  than 
  any 
  other 
  organic 
  

   life. 
  

  

  In 
  the 
  Dakota 
  Group 
  there 
  are 
  a 
  few 
  veins 
  of 
  brown 
  lignite, 
  which 
  is 
  

   always 
  an 
  inferior 
  variety 
  of 
  coal. 
  The 
  most 
  important 
  seam 
  extends 
  

   irregularly, 
  and 
  with 
  frequent 
  omissions, 
  from 
  the 
  State 
  line 
  in 
  Wash- 
  

   ington 
  and 
  Eepublic 
  Counties, 
  southwesterly 
  to 
  the 
  Arkansas 
  Valley. 
  

   It 
  varies 
  in 
  thickness 
  from 
  10 
  inches 
  to 
  40; 
  but 
  usually 
  a 
  portion 
  of 
  this 
  

   thickness 
  includes 
  seams 
  or 
  layers 
  of 
  clay-shale. 
  This 
  lignite 
  contains 
  

   a 
  large 
  percentage 
  of 
  ashes; 
  but 
  a 
  more 
  objectionable 
  feature 
  is 
  its 
  

   tendency 
  to 
  crumble 
  on 
  exposure 
  to 
  frost. 
  This 
  alone 
  renders 
  it 
  almost 
  

   worthless 
  as 
  a 
  marketable 
  coal. 
  At 
  some 
  localities 
  it 
  has 
  much 
  pyrites, 
  

   with 
  sulphur 
  so 
  free 
  as 
  to 
  cover 
  the 
  deposit 
  with 
  a 
  yellow 
  coating. 
  This 
  

   coal 
  sometimes 
  takes 
  fire 
  by 
  spontaneous 
  combustion. 
  Isotwithstanding 
  

   these 
  defects, 
  it 
  becomes 
  of 
  value 
  in 
  sparsely-timbered 
  counties, 
  by 
  fur- 
  

   nishing 
  to 
  the 
  settlers 
  a 
  cheap 
  fuel, 
  costing 
  only 
  the 
  time 
  and 
  labor 
  

   necessary 
  to 
  dig 
  and 
  convey 
  it 
  to 
  their 
  farms. 
  It 
  is 
  usually 
  mined 
  at 
  the 
  

   surface 
  in 
  the 
  open 
  air, 
  by 
  " 
  stripping", 
  t. 
  <?. 
  removing 
  the 
  few 
  feet 
  of 
  

   soil 
  or 
  shale 
  that 
  overlies 
  it. 
  An 
  average 
  outcrop 
  will 
  yield 
  at 
  least 
  a 
  

   ton 
  for 
  a 
  day's 
  labor. 
  It 
  is 
  found 
  in 
  Washington, 
  Eepublic, 
  Cloud, 
  

   Mitchell, 
  Lincoln, 
  Ottawa, 
  Saline, 
  Ellsworth, 
  McPherson, 
  Eice, 
  Barton, 
  

   and 
  perhaps 
  some 
  adjoining 
  counties. 
  These 
  lignite-beds 
  give 
  us 
  no 
  

   vegetable 
  remains 
  that 
  can 
  be 
  identified. 
  It 
  appears 
  to 
  be 
  of 
  a 
  low 
  

   swamp 
  type 
  unlike 
  the 
  leaves 
  so 
  higlily 
  characteristic 
  of 
  the 
  Dakota 
  

   group. 
  

  

  As 
  this 
  group 
  is 
  composed, 
  to 
  a 
  very 
  large 
  extent, 
  of 
  siliceous 
  sand- 
  

   stone, 
  the 
  first 
  impression 
  would 
  be 
  that 
  the 
  soil 
  would 
  naturally 
  be 
  poor 
  

   and 
  sandy. 
  This 
  is 
  not 
  the 
  case. 
  The 
  best 
  materials 
  of 
  the 
  soil 
  must 
  

   have 
  come 
  from 
  another 
  source, 
  and 
  must 
  have 
  been 
  from 
  the 
  later 
  

   divisions 
  of 
  the 
  Cretaceous 
  which 
  were 
  above 
  it. 
  We 
  find 
  the 
  Fort 
  Hays 
  

   limestones 
  and 
  limeshales 
  overlying 
  the 
  western 
  portion 
  of 
  Dakota,^ 
  

   and 
  other 
  indications 
  show 
  that 
  they 
  formerly 
  overspread 
  the 
  whole 
  of 
  

   it. 
  As 
  these 
  lime-deposits 
  are 
  now 
  disintegrating 
  by 
  rain, 
  frost, 
  and 
  

   other 
  agencies, 
  such 
  action 
  prevailing 
  for 
  a 
  long 
  period 
  would 
  have 
  com- 
  

   mingled 
  lime 
  with 
  the 
  sand 
  and 
  produced 
  a 
  fertile 
  soil. 
  

  

  The 
  farms 
  on 
  the 
  Dakota 
  show 
  as 
  much 
  natural 
  fertility 
  as 
  any 
  por- 
  

   tions 
  of 
  the 
  State. 
  The 
  moderately 
  sandy 
  subsoil 
  furnishes 
  a 
  natural 
  

  

  * 
  See 
  Haydeu's 
  Geological 
  Report 
  lor 
  1874, 
  p. 
  326. 
  

   tibid, 
  p.' 
  327. 
  

  

  