﻿MUDGE.] 
  CRETACEOUS 
  SYSTEM 
  NIOBRA.RA. 
  281 
  

  

  III.— 
  CRETACEOUS 
  SYSTEM. 
  

  

  1. 
  — 
  Niobrara. 
  

  

  2. 
  — 
  Dakota. 
  

  

  The 
  Cretaceous 
  in 
  Kansas 
  covers 
  an 
  area 
  of 
  over 
  40,000 
  square 
  miles, 
  

   or 
  more 
  than 
  half 
  of 
  the 
  surface 
  of 
  the 
  State. 
  The 
  Pierre 
  and 
  Fox 
  

   Hill 
  groups 
  of 
  Hay 
  den, 
  and 
  all 
  equivalents 
  of 
  those 
  periods, 
  are 
  en- 
  

   tirely 
  wanting. 
  The 
  Benton 
  group 
  also 
  appears 
  to 
  be 
  absent. 
  The 
  

   Cretaceous 
  is, 
  therefore, 
  represented 
  in 
  Kansas 
  by 
  the 
  Niobrara 
  and 
  

   Dakota 
  only. 
  The 
  line 
  of 
  demarkation 
  between 
  the 
  Pliocene 
  and 
  Cre- 
  

   taceous, 
  though 
  presenting 
  a 
  very 
  irregular 
  line, 
  is 
  well 
  defined 
  and 
  

   sharp. 
  Adjoining 
  the 
  Permian 
  easterly, 
  it 
  is 
  not 
  so 
  clear 
  ; 
  yet 
  some 
  

   recent 
  examinations, 
  made 
  in 
  company 
  with 
  Prof. 
  O. 
  St. 
  John, 
  show 
  

   that 
  the 
  boundary 
  is 
  not 
  difficult 
  to 
  trace. 
  We 
  have 
  never 
  been 
  able 
  

   to 
  find 
  any 
  fossils 
  of 
  the 
  Jurassic 
  or 
  Triassic, 
  the 
  beds 
  of 
  the 
  Creta- 
  

   ceous 
  resting 
  conformably 
  or 
  nearly 
  so 
  on 
  the 
  Permian. 
  

  

  That 
  portion 
  south 
  of 
  the 
  Arkansas 
  River 
  has 
  been 
  little 
  examined, 
  

   either 
  by 
  myself 
  or 
  others, 
  but 
  appears 
  to 
  be 
  represented 
  by 
  the 
  Fort 
  

   Hays 
  and 
  Dakota 
  groups. 
  

  

  1. 
  — 
  Niobrara. 
  

  

  a. 
  — 
  Niobrara. 
  

  

  h. 
  — 
  Fort 
  Hays. 
  

  

  The 
  Niobrara 
  of 
  Hayden, 
  or 
  its 
  equivalents 
  in 
  time, 
  is 
  well 
  repre- 
  

   sented. 
  It 
  is 
  divided 
  into 
  two 
  clearly-defined 
  portions, 
  by 
  a 
  massive 
  

   bed 
  of 
  limestone 
  or 
  yellow 
  chalk, 
  which, 
  when 
  fully 
  exposed, 
  where 
  it 
  

   has 
  not 
  suffered 
  from 
  abrasion, 
  is 
  60 
  feet 
  in 
  thickness. 
  It 
  is 
  seen 
  in 
  the 
  

   valley 
  of 
  the 
  Smoky, 
  southwest 
  of 
  Fort 
  Hays, 
  as 
  well 
  as 
  seven 
  miles 
  

   west 
  of 
  that 
  i)lace, 
  and 
  at 
  various 
  points 
  to 
  the 
  northeast, 
  crossing 
  the 
  

   Solomon 
  just 
  above 
  the 
  Forks, 
  near 
  Osborne 
  City, 
  and 
  entering 
  Nebraska 
  

   in 
  Republican 
  Valley, 
  near 
  where 
  that 
  river 
  crosses 
  the 
  State 
  line. 
  It 
  

   is 
  composed 
  of 
  layers 
  of 
  yellow 
  chalky 
  limestone, 
  from 
  1 
  to 
  3 
  feet 
  in 
  

   thickness. 
  It 
  makes 
  an 
  excellent 
  building-material, 
  working 
  easily, 
  yet 
  

   sufficiently 
  compact 
  to 
  be 
  used 
  for 
  stores 
  or 
  dwellings. 
  At 
  Hays, 
  the 
  

   school-house 
  and 
  court-house 
  are 
  built 
  from 
  it; 
  and 
  10 
  miles 
  west 
  of 
  

   that 
  place 
  the 
  Kansas 
  Pacific 
  Railway 
  has 
  opened 
  a 
  quarry 
  for 
  supply- 
  

   ing 
  stone 
  for 
  use 
  along 
  its 
  line. 
  It 
  also 
  burns 
  to 
  a 
  good 
  quicklime. 
  The 
  

   massiveness 
  and 
  persistence 
  of 
  this 
  stratum 
  make 
  it 
  a 
  well-defined 
  geo- 
  

   logical 
  horizon. 
  Below 
  this 
  line, 
  as 
  well 
  as 
  in 
  it, 
  vertebrate 
  fossils 
  are 
  

   few, 
  while 
  above 
  it 
  they 
  are 
  numerous 
  and 
  of 
  varied 
  type. 
  Its 
  fossils 
  

   Sive 
  Inoeerami, 
  fragments 
  of 
  Haploscapha^ 
  Ostrea, 
  with 
  occasional 
  remains 
  

   of 
  fish 
  and 
  Saurians. 
  The 
  vertebrates 
  are 
  always 
  so 
  rare 
  that 
  we 
  never 
  

   wasted 
  our 
  time 
  in 
  hunting 
  them 
  in 
  this 
  stratum 
  ; 
  still 
  our 
  largest 
  Sau- 
  

   rian, 
  Brimosaurus 
  of 
  Leidy, 
  was 
  found 
  in 
  it, 
  in 
  Jewell 
  County. 
  

  

  a. 
  — 
  Niobrara 
  proper. 
  

  

  The 
  Niobrara 
  in 
  Kansas 
  differs 
  from 
  the 
  sauie 
  deposit 
  in 
  Southern 
  

   Nebraska 
  and 
  on 
  Niobrara 
  River. 
  This 
  diflerence 
  is 
  seen 
  in 
  the 
  physi- 
  

   cal 
  features, 
  but 
  more 
  particularly 
  in 
  the 
  fossils. 
  In 
  Kansas 
  it 
  has 
  more 
  

   of 
  the 
  composition 
  of 
  clear 
  chalky 
  deposit. 
  In 
  its 
  fossils, 
  it 
  gives 
  us 
  a 
  

  

  