﻿176 
  T. 
  E. 
  Savage 
  — 
  Devonian 
  Formation 
  of 
  Illinois. 
  

  

  species 
  of 
  Zaphrentis, 
  Leptostrophia 
  perplana, 
  Rhipido- 
  

   mella 
  cf. 
  penelope, 
  Amphigenia 
  curta, 
  Spirifer 
  duode- 
  

   narius, 
  Spirifer 
  macrothyris, 
  and 
  Odontocephalus 
  sp., 
  

   several 
  of 
  which 
  also 
  occur 
  in 
  the 
  overlying 
  Grand 
  Tower 
  

   limestone 
  into 
  which 
  the 
  sandstone 
  grades 
  through 
  a 
  

   transition 
  zone 
  of 
  8 
  or 
  10 
  feet 
  without 
  any 
  interruption 
  

   of 
  deposition. 
  

  

  Grand 
  Tower 
  Limestone. 
  — 
  The 
  limestone 
  conformably 
  

   overlying 
  the 
  Dutch 
  Creek 
  sandstone 
  is 
  rather 
  thick- 
  

   bedded, 
  and 
  coarsely 
  crystalline, 
  and 
  has 
  a 
  total 
  thick- 
  

   ness 
  of 
  about 
  125 
  feet. 
  It 
  contains 
  a 
  large 
  fauna, 
  

   comprising 
  species 
  which 
  clearly 
  indicate 
  the 
  Onondaga 
  

   age 
  of 
  the 
  strata, 
  of 
  which 
  the 
  following 
  are 
  the 
  most 
  

   common: 
  Nucleocrinus 
  verneuili, 
  Stropheodonta 
  pater- 
  

   soni, 
  Ghonetes 
  honinchianus 
  , 
  Productella 
  spinulicosta 
  y 
  

   Gamarophoria 
  gainesi, 
  Pentamerella 
  arata, 
  Spirifer 
  

   acuminatus, 
  S. 
  duodenarius, 
  S. 
  gregarius, 
  S. 
  segmentum, 
  

   S. 
  grieri, 
  S. 
  macrothyris, 
  and 
  Odontocephalus 
  cegeria. 
  

  

  The 
  strata 
  are 
  well 
  exposed 
  in 
  the 
  north 
  half 
  of 
  the 
  

   Back-bone 
  ridge 
  north 
  of 
  Grand 
  Tower, 
  and 
  in 
  the 
  

   Bake-oven 
  mound 
  a 
  little 
  farther 
  north. 
  They 
  are 
  also 
  

   exposed 
  in 
  an 
  old 
  quarry 
  a 
  short 
  distance 
  east 
  of 
  Grand 
  

   Tower, 
  from 
  which 
  town 
  the 
  name 
  Grand 
  Tower 
  7 
  lime- 
  

   stone 
  has 
  been 
  applied 
  to 
  the 
  formation. 
  

  

  Misenheimer 
  Shale. 
  — 
  A 
  sedimentary 
  break 
  appears 
  to 
  

   have 
  occurred 
  everywhere 
  in 
  this 
  region 
  at 
  the 
  top 
  of 
  

   the 
  Grand 
  Tower 
  limestone. 
  The 
  succeeding 
  strata 
  

   correspond 
  in 
  age 
  to 
  the 
  Marcellus 
  and 
  Hamilton 
  of 
  the 
  

   New 
  York 
  section. 
  They 
  overlap 
  the 
  Grand 
  Tower 
  

   limestone 
  in 
  a 
  few 
  places, 
  and 
  in 
  these 
  the 
  basal 
  part 
  is 
  

   a 
  dark 
  shale 
  which 
  has 
  a 
  greatly 
  disturbed 
  appearance 
  

   and 
  contains 
  numerous 
  shells 
  of 
  Leiorhynchus 
  limitare, 
  

   and 
  a 
  few 
  other 
  fossils. 
  This 
  shale 
  member 
  has 
  a 
  thick- 
  

   ness 
  of 
  12 
  to 
  25 
  feet, 
  and 
  is 
  well 
  exposed 
  in 
  the 
  banks 
  

   of 
  Misenheimer 
  creek 
  and 
  its 
  tributaries 
  in 
  the 
  N.E.%, 
  

   sec. 
  34, 
  and 
  the 
  N.W. 
  1 
  ^, 
  sec. 
  35, 
  in 
  Misenheimer 
  town- 
  

   ship, 
  Union 
  County, 
  where 
  it 
  rests 
  unconformably 
  upon 
  

   the 
  Clear 
  Creek 
  chert 
  or 
  the 
  Dutch 
  Creek 
  sandstone. 
  It 
  

   may 
  be 
  appropriately 
  referred 
  to 
  as 
  the 
  Misenheimer 
  

   shale. 
  

  

  Lingle 
  Limestone. 
  — 
  Resting 
  conformably 
  upon 
  the 
  

   Misenheimer 
  shale 
  where 
  that 
  is 
  present, 
  and 
  uncon- 
  

   formably 
  upon 
  the 
  Grand 
  Tower 
  limestone 
  or 
  some 
  older 
  

  

  7 
  Savage, 
  T. 
  E. 
  : 
  Illinois 
  State 
  Acad, 
  of 
  Sci., 
  Trans., 
  3, 
  116-132, 
  1910. 
  

  

  