﻿408 
  Twenhofel 
  — 
  Wreford 
  and 
  Foraker 
  Limestones. 
  

  

  The 
  Foraker 
  Limestone 
  Member. 
  

  

  The 
  Foraker 
  limestone 
  forms 
  the 
  summit 
  of 
  an 
  import- 
  

   ant 
  escarpment 
  in 
  southeastern 
  Cowley 
  County, 
  Kansas, 
  

   and 
  western 
  Osage 
  County, 
  Oklahoma. 
  Its 
  correlative 
  

   in 
  the 
  Kansas 
  River 
  section 
  has 
  not 
  been 
  determined. 
  

  

  The 
  thickness 
  of 
  the 
  limestone 
  averages 
  about 
  seventy- 
  

   five 
  feet. 
  There 
  is 
  some 
  variation 
  in 
  the 
  thickness, 
  which 
  

   in 
  places 
  rises 
  to 
  one 
  hundred 
  feet, 
  but 
  whether 
  there 
  is 
  a 
  

   systematic 
  increase 
  or 
  decrease 
  in 
  any 
  direction 
  has 
  not 
  

   been 
  determined. 
  

  

  The 
  greater 
  part 
  of 
  the 
  member 
  consists 
  of 
  limestone, 
  

   but 
  thin 
  beds 
  of 
  shale 
  and 
  shale 
  partings 
  are 
  present. 
  

   Much 
  of 
  the 
  limestone 
  is 
  not 
  very 
  resistant 
  and 
  these 
  por- 
  

   tions 
  are 
  commonly 
  covered 
  with 
  soil, 
  or 
  weathered 
  pro- 
  

   ducts 
  from 
  overlying 
  strata. 
  Exposures 
  of 
  the 
  strong 
  

   thick 
  beds, 
  in 
  particular 
  their 
  upper 
  portions, 
  are 
  of 
  

   abundant 
  occurrence. 
  

  

  The 
  Foraker 
  limestone 
  is 
  extremely 
  fossiliferous, 
  but 
  

   the 
  number 
  of 
  common 
  species 
  is 
  few. 
  Some 
  beds 
  are 
  

   literally 
  jammed 
  with 
  Fusulina, 
  others 
  have 
  them 
  in 
  a 
  

   few 
  individuals. 
  An 
  interesting 
  feature 
  connected 
  with 
  

   the 
  occurrence 
  of 
  Fusulina 
  is 
  that 
  in 
  some 
  beds 
  the 
  shells 
  

   are 
  enclosed 
  in 
  a 
  coating 
  of 
  calcium 
  carbonate. 
  This, 
  

   however, 
  is 
  not 
  peculiar 
  to 
  this 
  horizon. 
  The 
  incrus- 
  

   tation 
  is 
  believed 
  to 
  be 
  of 
  algal 
  origin. 
  Other 
  fossils 
  

   which 
  are 
  not 
  uncommon 
  are 
  Aulopora 
  (?) 
  anna, 
  Com- 
  

   posita 
  subtilita, 
  species 
  of 
  Froductus, 
  species 
  of 
  bryozoa, 
  

   and 
  fragments 
  of 
  crinoids. 
  

  

  Some 
  beds 
  of 
  the 
  member 
  contain 
  numerous 
  chert 
  nod- 
  

   ules, 
  the 
  exact 
  horizons 
  of 
  which 
  in 
  many 
  instances 
  are 
  

   not 
  readily 
  determinable. 
  On 
  fresh 
  surfaces 
  the 
  chert 
  

   nodules 
  are 
  not 
  particularly 
  conspicuous, 
  but 
  little 
  diffi- 
  

   culty 
  is 
  experienced 
  in 
  finding 
  them. 
  Weathering 
  of 
  the 
  

   limestones 
  brings 
  the 
  chert 
  into 
  relief 
  and 
  ultimately 
  con- 
  

   centrates 
  it 
  on 
  the 
  surface. 
  The 
  chert 
  is 
  abundantly 
  fos- 
  

   siliferous 
  at 
  all 
  localities 
  where 
  it 
  was 
  examined, 
  — 
  some 
  

   four 
  or 
  five 
  hundred. 
  Nodules 
  in 
  which 
  fossils 
  are 
  not 
  

   present 
  apparently 
  are 
  extremely 
  rare. 
  The 
  nodulesdo 
  

   not 
  nppear 
  to 
  attain 
  a 
  great 
  size 
  — 
  five 
  to 
  six 
  inches 
  being 
  

   about 
  the 
  average 
  — 
  and 
  they 
  are 
  of 
  irregular 
  shapes. 
  

   The 
  chert 
  is 
  quite 
  porous, 
  the 
  cavities 
  in 
  large 
  part 
  

   appearing 
  to 
  be 
  molds 
  of 
  small 
  fragments 
  of 
  fossils. 
  

  

  