﻿Tivenhofel 
  — 
  Wreford 
  and 
  Foraker 
  Limestones. 
  ^07 
  

  

  Aet. 
  XXVII. 
  — 
  The 
  Chert 
  of 
  the 
  Wreford 
  and 
  Foraker 
  

   Limestones 
  along 
  the 
  State 
  Line 
  of 
  Kansas 
  and 
  Okla- 
  

   homa; 
  by 
  W. 
  H. 
  Twekhofel. 
  

  

  Introduction. 
  

  

  The 
  Foraker 
  limestone 
  member. 
  

  

  The 
  "Wreford 
  limestone 
  member. 
  

  

  Kelations 
  of 
  the 
  cherts 
  to 
  the 
  associated 
  limestones. 
  

  

  Description 
  of 
  the 
  cherts. 
  

  

  Source 
  of 
  the 
  silica. 
  

  

  Time 
  and 
  method 
  of 
  origin 
  of 
  the 
  chert. 
  

  

  Theory 
  that 
  the 
  chert 
  is 
  a 
  consequence 
  of 
  weathering. 
  

  

  Theory 
  that 
  the 
  chert 
  developed 
  through 
  filling 
  of 
  cavities, 
  or 
  replace- 
  

   ment 
  of 
  solid 
  rock. 
  

  

  Theory 
  that 
  the 
  chert 
  nodules 
  resulted 
  from 
  direct 
  precipitation 
  of 
  

   silica 
  from 
  sea 
  water. 
  

  

  Theory 
  of 
  partial 
  replacement 
  of 
  unconsolidated 
  lime 
  sediments 
  either 
  

   before 
  or 
  during 
  the 
  process 
  of 
  consolidation. 
  

   Resume 
  of 
  facts 
  anel 
  conclusions. 
  

  

  Introduction. 
  

  

  Chert 
  is 
  abundantly 
  distributed 
  throughout 
  the 
  Penn- 
  

   sylvanian 
  and 
  lower 
  Permian 
  strata 
  of 
  Kansas 
  and 
  Okla- 
  

   homa, 
  and 
  its 
  presence 
  scarcely 
  ever 
  fails 
  to 
  attract 
  the 
  

   observer's 
  attention, 
  even 
  though 
  he 
  is 
  not 
  a 
  geologist. 
  

   In 
  some 
  sections 
  it 
  so 
  thoroughly 
  litters 
  the 
  fields 
  as 
  to 
  

   make 
  them 
  unfit 
  for 
  cultivation. 
  There 
  are 
  other 
  sec- 
  

   tions 
  where 
  it 
  is 
  extremely 
  abundant; 
  but 
  not 
  sufficiently 
  

   so 
  to 
  prohibit 
  cultivation. 
  Over 
  these 
  areas 
  the 
  chert 
  

   has 
  been 
  gathered 
  into 
  heaps 
  in 
  the 
  hollows 
  or 
  along 
  the 
  

   borders 
  of 
  the 
  parts 
  cultivated. 
  It 
  is 
  used 
  as 
  road 
  mate- 
  

   rial 
  in 
  many 
  of 
  the 
  counties 
  in 
  which 
  it 
  occurs, 
  and 
  its 
  use 
  

   for 
  this 
  purpose 
  is 
  certain 
  to 
  be 
  more 
  extensive 
  in 
  the 
  

   future. 
  

  

  It 
  is 
  quite 
  probable 
  that 
  some 
  chert 
  is 
  present 
  in 
  prac- 
  

   tically 
  every 
  important 
  limestone 
  member 
  of 
  the 
  Pennsyl- 
  

   vanian 
  and 
  Permian 
  systems 
  of 
  Kansas 
  and 
  adjacent 
  

   states 
  and 
  it 
  is 
  extremely 
  common 
  or 
  abundant 
  in 
  many 
  

   members 
  ; 
  the 
  Winterset, 
  Oread, 
  Foraker 
  and 
  Wreford 
  

   limestones 
  containing 
  it 
  in 
  large 
  quantities. 
  In 
  this 
  

   paper 
  only 
  those 
  cherts 
  are 
  considered 
  which 
  occur 
  in 
  the 
  

   Foraker 
  and 
  Wreford 
  members. 
  

  

  For 
  the 
  opportunity 
  of 
  studying 
  these 
  cherts 
  in 
  the 
  field 
  

   the 
  writer 
  is 
  indebted 
  to 
  Mr. 
  B. 
  E. 
  LaDow 
  of 
  Fredonia, 
  

   Kansas. 
  The 
  suggestions 
  and 
  criticisms 
  of 
  the 
  writer's 
  

   colleagues, 
  Professors 
  Winchell 
  and 
  Mead, 
  have 
  greatly 
  

   aided 
  in 
  the 
  preparation 
  of 
  the 
  article. 
  

  

  Am. 
  Jour. 
  Sci.— 
  Fourth 
  Series, 
  Vol. 
  XLVIT, 
  No. 
  282.— 
  June, 
  1019. 
  

   28 
  

  

  