﻿Mississippian 
  of 
  Ohio 
  and 
  Pennsylvania. 
  

  

  305 
  

  

  Fig. 
  3 
  shows 
  that 
  the 
  thickness 
  increases 
  noticeably 
  from 
  

   east 
  to 
  west, 
  also 
  that 
  the 
  formation 
  has 
  a 
  definite 
  sandstone 
  

   horizon 
  toward 
  the 
  west 
  which 
  separates 
  the 
  Brecksville 
  from 
  

   the 
  Sunbury 
  shale. 
  This 
  is 
  the 
  Aurora 
  sandstone. 
  

  

  Berea 
  formation 
  : 
  This 
  formation 
  is 
  considered 
  by 
  far 
  the 
  

   most 
  important 
  of 
  the 
  Mississippian 
  formations 
  in 
  the 
  territory 
  

   surveyed. 
  In 
  Pennsylvania 
  it 
  is 
  subdivided 
  into 
  the 
  Cusse- 
  

   wago 
  sandstone, 
  Cussewago 
  shale 
  and 
  Corry 
  sandstone, 
  of 
  

  

  Ho 
  

  

  7+ 
  

  

  ~\ 
  

  

  Fig. 
  3. 
  

  

  ?z 
  

  

  2f/J 
  

  

  3/1 
  

  

  7? 
  

  

  

  'A 
  

  

  Rq^sg, 
  

  

  'Kyi:'; 
  

  

  cv 
  r 
  

  

  wm 
  

  

  ^r 
  

  

  rii'iiM 
  

  

  <l 
  

  

  c 
  % 
  

  

  ££:3*anfiig' 
  

  

  ccp 
  

  

  -^•IL 
  

  

  uilto 
  

  

  lift 
  

  

  Fig. 
  3. 
  Sections 
  showing 
  the 
  Orangeville 
  formation. 
  

  

  which 
  the 
  first 
  two 
  are 
  unimportant 
  because 
  they 
  are 
  only 
  local 
  

   in 
  extent. 
  The 
  Berea 
  is 
  to 
  a 
  large 
  extent 
  the 
  key 
  horizon 
  to 
  

   the 
  stratigraphy 
  not 
  only 
  of 
  the 
  district 
  under 
  discussion 
  but 
  

   also 
  of 
  the 
  region 
  to 
  the 
  south. 
  Therefore 
  much 
  time 
  and 
  care 
  

   were 
  spent 
  in 
  tracing 
  it 
  accurately. 
  All 
  described 
  exposures 
  

   were 
  visited 
  and 
  many 
  new 
  sections 
  involving 
  its 
  nature 
  or 
  

   position 
  were 
  made. 
  A 
  careful 
  search 
  for 
  fossils 
  was 
  also 
  

   instituted, 
  but 
  none 
  were 
  found. 
  I. 
  C. 
  White, 
  who 
  has 
  perhaps 
  

   done 
  more 
  detailed 
  work 
  in 
  this 
  region 
  than 
  any 
  other 
  geolo- 
  

   gist, 
  mentions 
  finding 
  fossils 
  only 
  at 
  two 
  localities.* 
  One 
  is 
  at 
  

   Corry, 
  where, 
  he 
  states, 
  the 
  formation 
  contains 
  a 
  " 
  few 
  ill-pre- 
  

   served 
  fossils." 
  The 
  other 
  is 
  " 
  east 
  of 
  the 
  county 
  line 
  (Craw- 
  

  

  * 
  Second 
  Geol. 
  Surv. 
  Pa., 
  vol. 
  Q 
  4 
  , 
  p. 
  92. 
  

  

  