﻿18H 
  S. 
  Weller— 
  Succession 
  of 
  Fossil 
  Faunas 
  in 
  Missouri. 
  

  

  The 
  limits 
  of 
  these 
  zones, 
  however, 
  are 
  not 
  sharply 
  defined, 
  as 
  

   lower 
  faunas 
  change 
  to 
  the 
  ones 
  above 
  through 
  gradual 
  transi- 
  

   tions. 
  

  

  As 
  the 
  fauna 
  of 
  the 
  Keokuk 
  beds 
  in 
  Illinois 
  and 
  Iowa 
  has 
  

   been 
  shown 
  to 
  be 
  simply 
  a 
  later 
  product 
  of 
  the 
  same 
  line 
  of 
  

   development 
  which 
  took 
  place 
  during 
  the 
  deposition 
  of 
  the 
  

   Burlington 
  beds, 
  so 
  here 
  in 
  Southwest 
  Missouri, 
  the 
  upper 
  

   faunas, 
  which 
  represent 
  the 
  Keokuk, 
  are 
  only 
  a 
  continuation 
  of 
  

   the 
  development 
  seen 
  in 
  the 
  lower 
  beds. 
  Prof. 
  H. 
  S. 
  Williams 
  

   has 
  suggested 
  the 
  name 
  Osage 
  Group* 
  for 
  this 
  whole 
  series 
  of 
  

   strata 
  in 
  Missouri, 
  while 
  Mr. 
  C. 
  R. 
  Keyes 
  has 
  adopted 
  the 
  

   name 
  Augusta 
  Groupf 
  for 
  the 
  same 
  deposits. 
  With 
  the 
  excep- 
  

   tion 
  of 
  the 
  lowest 
  beds, 
  the 
  Springfield 
  limestones 
  resemble 
  

   their 
  more 
  eastern 
  equivalents 
  in 
  Illinois 
  and 
  Iowa, 
  both 
  in 
  

   lithological 
  and 
  in 
  faunal 
  characters. 
  

  

  The 
  great 
  difficulty 
  experienced 
  in 
  this 
  study, 
  has 
  been 
  the 
  

   lack 
  of 
  any 
  continuous 
  section 
  comprising 
  all 
  the 
  beds 
  of 
  the 
  

   group, 
  such 
  as 
  is 
  shown 
  in 
  the 
  Mississippi 
  River 
  section. 
  Some 
  

   twenty-five 
  localities 
  were 
  studied, 
  and 
  from 
  them 
  more 
  or 
  less 
  

   complete 
  collections 
  of 
  the 
  fossils 
  were 
  made. 
  

  

  Most 
  instructive 
  in 
  the 
  way 
  of 
  showing 
  the 
  succession 
  of 
  the 
  

   faunas, 
  is 
  a 
  series 
  of 
  sections 
  along 
  the 
  Gulf 
  railroad, 
  from 
  

   Jones 
  Spring, 
  four 
  miles 
  southeast 
  of 
  Springfield, 
  to 
  the 
  Gulf 
  

   railroad 
  shops 
  in 
  the 
  city, 
  then 
  turning 
  to 
  the 
  south 
  and 
  

   extending 
  along 
  Wilson 
  Creek 
  to 
  Mackey's 
  quarry. 
  These 
  sec- 
  

   tions 
  show 
  the 
  succession 
  from 
  near 
  the 
  base 
  of 
  the 
  Burlington 
  

   up 
  into 
  the 
  Keokuk. 
  Along 
  this 
  line 
  the 
  rocks 
  dip 
  gradually 
  

   to 
  the 
  west, 
  and 
  in 
  the 
  successive 
  cuts 
  and 
  quarries, 
  starting 
  

   from 
  Jones 
  Spring, 
  successively 
  higher 
  beds 
  are 
  exposed. 
  At 
  

   one 
  point, 
  a 
  short 
  distance 
  east 
  of 
  Springfield, 
  a 
  slight 
  fault 
  

   disturbs 
  the 
  regularity 
  of 
  the 
  line 
  of 
  sections, 
  otherwise 
  it 
  is 
  

   continuous. 
  Besides 
  this 
  series 
  of 
  sections, 
  other 
  more 
  or 
  less 
  

   isolated 
  outcrops 
  were 
  studied. 
  

  

  There 
  being 
  no 
  continuous 
  section, 
  and 
  the 
  element 
  of 
  dip 
  

   being 
  uncertain, 
  no 
  accurate 
  estimate 
  of 
  the 
  aggregate 
  thick- 
  

   ness 
  of 
  these 
  beds 
  can 
  be 
  made, 
  but 
  they 
  probably 
  extend 
  

   through 
  one 
  or 
  two 
  hundred 
  feet. 
  

  

  Description 
  of 
  Zones. 
  

  

  Zone 
  I. 
  — 
  This 
  zone 
  can 
  be 
  readily 
  recognized 
  wherever 
  it 
  

   occurs. 
  Its 
  lithological 
  characters 
  are, 
  in 
  general, 
  distinct 
  

   from 
  any 
  of 
  the 
  succeeding 
  beds. 
  It 
  is 
  a 
  finegrained, 
  gray 
  or 
  

   bluish 
  limestone, 
  quite 
  hard, 
  and 
  with 
  a 
  more 
  or 
  less 
  marked 
  

   conchoidal 
  fracture. 
  Some 
  lenticular 
  chert 
  nodules 
  occur 
  

  

  *Bul1. 
  "0. 
  S. 
  Geol. 
  Surv., 
  No. 
  80, 
  p. 
  109. 
  Washington, 
  1891. 
  

   f 
  Iowa 
  Geol. 
  Surv., 
  toI. 
  i, 
  p. 
  59. 
  Des 
  Moines, 
  1893. 
  

  

  