﻿T. 
  E. 
  Savage 
  — 
  Devonian 
  Formation 
  of 
  Illinois. 
  177 
  

  

  formation 
  where 
  the 
  shale 
  is 
  absent, 
  is 
  a 
  dark 
  colored, 
  

   somewhat 
  shaly, 
  hard, 
  brittle 
  limestone 
  that 
  contains 
  

   such 
  characteristic 
  Hamilton 
  fossils 
  as 
  Micro 
  cyclus 
  dis- 
  

   cus, 
  Chonetes 
  pusillus, 
  C. 
  coronatus, 
  Tropidoleptus 
  

   carinatus, 
  Vitulina 
  pustulosa, 
  Athyris 
  spiriferoides, 
  

   Spirifer 
  audaculus, 
  S. 
  fornacula, 
  S. 
  granulosus, 
  and 
  S. 
  

   pennatus. 
  The 
  lower 
  part 
  of 
  this 
  limestone 
  outcrops 
  

   near 
  the 
  top 
  at 
  the 
  north 
  end 
  of 
  the 
  Devil's 
  Back-bone 
  

   ridge, 
  north 
  of 
  Grand 
  Tower, 
  and 
  the 
  entire 
  thickness 
  

   of 
  the 
  formation 
  is 
  present 
  along 
  a 
  branch 
  of 
  Clear 
  creek 
  

   in 
  the 
  N.E.%, 
  sec. 
  34, 
  T.11S., 
  R.2W., 
  about 
  one 
  and 
  one- 
  

   fourth 
  miles 
  southwest 
  of 
  Mountain 
  Glen. 
  It 
  is 
  also 
  

   exposed 
  above 
  the 
  Misenheimer 
  shale 
  along 
  a 
  branch 
  of 
  

   Lingle 
  creek 
  in 
  the 
  S.W.%, 
  sec. 
  26, 
  T.13S., 
  R.2W., 
  and 
  it 
  

   is 
  proposed 
  to 
  refer 
  to 
  this 
  formation 
  as 
  the 
  Lingle 
  

   limestone. 
  

  

  Upper 
  Devonian. 
  

  

  Alto 
  Formation. 
  — 
  Overlying 
  the 
  Lingle 
  limestone 
  

   southwest 
  of 
  Mountain 
  Glen 
  and 
  in 
  other 
  places 
  in 
  sec- 
  

   tions 
  11, 
  23, 
  26 
  and 
  36, 
  T.12S., 
  R.2W., 
  is 
  a 
  dark, 
  siliceous 
  

   shale 
  and 
  somewhat 
  shaly 
  limestone, 
  40 
  to 
  75 
  feet 
  thick, 
  

   which 
  contains 
  the 
  fossils 
  Chonetes 
  sp., 
  Leiorhynchus 
  

   globuliforme, 
  L. 
  mesaco 
  stale, 
  Spirifer 
  pennatus, 
  Reticu- 
  

   laria 
  Icevis, 
  and 
  Tentaculites 
  sp. 
  From 
  the 
  exposure 
  of 
  

   this 
  limestone 
  along 
  a 
  creek 
  in 
  the 
  N.E.14, 
  sec. 
  34, 
  in 
  

   Alto 
  township 
  (Union 
  County), 
  it 
  will 
  be 
  designated 
  the 
  

   Alto 
  formation. 
  This 
  formation 
  is 
  thought 
  to 
  repre- 
  

   sent 
  about 
  the 
  time 
  of 
  deposition 
  of 
  the 
  Portage 
  or 
  

   Chemung 
  deposits 
  of 
  the 
  New 
  York 
  section. 
  

  

  Mountain 
  Glen 
  Shale.-^-At 
  the 
  locality 
  last 
  mentioned, 
  

   a 
  hard, 
  black, 
  laminated 
  shale 
  having 
  a 
  band 
  of 
  iron 
  

   pyrites 
  in 
  the 
  basal 
  part 
  and 
  containing 
  numerous 
  spores 
  

   of 
  Sporangites 
  huronensis, 
  and 
  shells 
  of 
  a 
  linguloid, 
  

   Barroisella 
  spatulata, 
  unconformably 
  overlies 
  the 
  Alto 
  

   formation. 
  This 
  shale 
  is 
  present 
  in 
  several 
  other 
  places 
  

   north 
  of 
  Jonesboro 
  in 
  Union 
  County, 
  where 
  it 
  rests 
  un- 
  

   conformably 
  on 
  the 
  Alto 
  limestone. 
  The 
  thickness 
  of 
  

   the 
  shale 
  ranges 
  from 
  25 
  to 
  45 
  feet, 
  and 
  it 
  is 
  probably 
  

   to 
  be 
  correlated 
  with 
  the 
  upper 
  part 
  of 
  the 
  New 
  Albany 
  

   black 
  shale 
  of 
  Indiana, 
  and 
  the 
  Chattanooga 
  black 
  shale 
  

   of 
  Tennessee. 
  One 
  of 
  the 
  best 
  exposures 
  may 
  be 
  seen 
  

   along 
  a 
  stream 
  about 
  three 
  and 
  one-half 
  miles 
  N.W. 
  of 
  

   Jonesboro, 
  in 
  the 
  S.W.%, 
  sec, 
  11, 
  T.12S., 
  E.2W. 
  A 
  good 
  

  

  