﻿430 
  Gould 
  — 
  Phases 
  of 
  the 
  Dakota 
  Cretaceous 
  in 
  Nebraska. 
  

  

  area 
  of 
  outcrops 
  is 
  about 
  two 
  hundred 
  and 
  fifty 
  miles 
  long 
  and 
  

   on 
  an 
  average 
  thirty-five 
  miles 
  wide, 
  extending 
  crescent-like 
  

   through 
  Fairbury, 
  Beatrice, 
  Lincoln, 
  Louisville, 
  Blair, 
  Teka- 
  

   mah, 
  Decatur 
  and 
  Ponca. 
  Dakota 
  City, 
  from 
  which 
  the 
  group 
  

   was 
  named, 
  is 
  ten 
  or 
  more 
  miles 
  from 
  the 
  nearest 
  bluff. 
  

  

  For 
  the 
  most 
  part 
  the 
  Dakota 
  in 
  Nebraska 
  consists 
  of 
  rather 
  

   soft 
  reddish 
  brown 
  or 
  gray 
  sandstone, 
  usually 
  in 
  ledges 
  or 
  

   lenses, 
  imbedded 
  between 
  strata 
  of 
  more 
  or 
  less 
  arenaceous 
  

   clay 
  shales. 
  These 
  shales 
  greatly 
  predominate, 
  perhaps 
  in 
  

   most 
  places 
  comprising 
  two-thirds 
  to 
  three-fourths 
  of 
  the 
  entire 
  

   thickness 
  of 
  the 
  formation. 
  In 
  color 
  they 
  are 
  whitish, 
  or 
  

   bluish 
  with 
  many 
  strata 
  of 
  red 
  or 
  brown, 
  caused, 
  as 
  in 
  the 
  

   case 
  of 
  the 
  sandstone, 
  by 
  the 
  presence 
  of 
  iron. 
  The 
  reason 
  

   that 
  the 
  shales 
  are 
  usually 
  so 
  seldom 
  noticed 
  may 
  be 
  accounted 
  

   for 
  by 
  the 
  fact 
  that 
  they 
  weather 
  very 
  readily 
  and 
  their 
  out- 
  

   crops 
  are 
  generally 
  occupied 
  by 
  covered 
  slopes. 
  On 
  the 
  other 
  

   hand, 
  the 
  relatively 
  harder 
  sandstone 
  forms 
  the 
  conspicuous 
  

   bluffs, 
  mesas 
  and 
  escarpments 
  which 
  give 
  to 
  the 
  Dakota 
  region 
  

   its 
  characteristic 
  contour. 
  

  

  The 
  clays 
  and 
  shales 
  form 
  an 
  important 
  economic 
  phase 
  of 
  

   the 
  Dakota. 
  They 
  have 
  been 
  excavated 
  at 
  several 
  localities 
  in 
  

   the 
  State, 
  furnishing 
  an 
  excellent 
  quality 
  of 
  brick, 
  tile, 
  etc. 
  

   Endicott, 
  Beatrice, 
  Lincoln 
  and 
  Louisville 
  in 
  Nebraska 
  and 
  

   Sioux 
  City 
  and 
  Sargeant's 
  Bluff 
  in 
  Iowa 
  are 
  points 
  from 
  

   which 
  clay 
  for 
  this 
  purpose 
  has 
  been 
  obtained. 
  As 
  the 
  supply 
  

   is 
  practically 
  inexhaustible 
  and 
  the 
  quality 
  exceptionally 
  good, 
  

   the 
  Dakota 
  clays 
  promise 
  to 
  become 
  an 
  important 
  economic 
  

   factor. 
  

  

  The 
  sandstone 
  is 
  used 
  for 
  building 
  purposes 
  in 
  a 
  number 
  of 
  

   localities 
  in 
  the 
  State. 
  The 
  entire 
  line 
  of 
  outcrops 
  from 
  Sioux 
  

   City 
  to 
  Kansas 
  may 
  be 
  traced 
  by 
  the 
  brown 
  sandstone 
  founda- 
  

   tions 
  of 
  houses 
  and 
  outbuildings. 
  As 
  a 
  general 
  rule, 
  however, 
  

   large 
  buildings 
  are 
  not 
  constructed 
  of 
  the 
  Dakota 
  sandstone, 
  

   although 
  at 
  Endicott, 
  Beatrice, 
  Louisville 
  and 
  other 
  places 
  

   these 
  may 
  be 
  found. 
  The 
  reasons 
  for 
  this 
  are 
  twofold 
  ; 
  first, 
  

   the 
  Permian 
  or 
  Carboniferous 
  limestones, 
  which 
  are 
  exception- 
  

   ally 
  fine 
  building 
  material, 
  are 
  nowhere 
  far 
  distant 
  ; 
  and 
  

   second, 
  the 
  Dakota 
  itself 
  is 
  not, 
  as 
  a 
  usual 
  thing, 
  a 
  first-class 
  

   stone 
  for 
  building 
  purposes. 
  Representing 
  all 
  degrees 
  of 
  hard- 
  

   ness 
  from 
  loose 
  sand 
  scarcely 
  cemented 
  together 
  to 
  the 
  hard 
  

   brittle 
  ironstone 
  concretions, 
  it 
  is 
  usually 
  too 
  soft 
  to 
  withstand 
  

   erosion 
  or 
  too 
  hard 
  to 
  be 
  dressed. 
  Ledges 
  yielding 
  suitable 
  

   building 
  stone 
  are 
  comparatively 
  rare. 
  

  

  At 
  least 
  one 
  locality 
  in 
  the 
  State 
  furnishes 
  a 
  ledge 
  of 
  Dakota 
  

   which 
  is 
  quite 
  unique. 
  About 
  five 
  miles 
  northwest 
  of 
  Fair- 
  

   bury, 
  Nebraska, 
  on 
  Whiskey 
  Run, 
  near 
  the 
  home 
  of 
  Mr. 
  

   Oberhelmen, 
  is 
  a 
  ledge 
  some 
  three 
  feet 
  thick 
  of 
  an 
  extremely 
  

  

  