444  CONTRIBUTIONS    TO    ECONOMIC    GEOLOGY,  1905. 
miles  up  tne  river,  but  so  far  as  seen  this  horizon  does  not  yield  workable  clay  in  the  region 
about  McGees. 
In  regard  to  the  quality  of  the  clay  on  the  Susquehanna  and  Roaring  Run  drainage  the 
best  evidence  of  its  excellence  is  the  extensive  use  that  is  being  made  of  it.  Large  mines 
are  in  operation  west  and  northwest  of  Curwensville  and  along  Roaring  Run  from  Wood- 
land to  Wallaceton.  The  clay  about  Burly  and  west  of  Blue  Ball  is  also  mined,  in  a  num- 
ber of  cases  being  hauled  by  wagon  to  the  railroad. 
Flint  clay  also  occurs  in  this  region  at  what  is  supposed  to  be  the  horizon  of  the  Middle 
Kittanning  coal.  It  was  seen  at  several  points  near  Westover  and  a  few  miles  southwest 
of  McCartney.  At  one  opening  near  Westover  the  clay  measured  from  3  to  5  feet.  The 
outcrop  near  McCartney  was  noted  in  the  grading  of  a  switch  running  southwest  to  a  small 
mine. 
.  Northeastern  Indiana  County. — Flint  clay  was  noted  at  a  number  of  points  in  the  north- 
east corner  of  Indiana  County,  though  at  none  of  these  points  could  an  examination  be 
made  to  determine  either  the  thickness  or  quality  of  the  clay.  On  Little  Mahoning  Creek 
flint  elav  was  noted  northeast  of  Richmond,  a  little  north  of  the  old  station  of  Enterprise, 
associated  with  whal  was  considered  to  be  the  "B"  coal.  North  of  Deckers  Point  it  out- 
crops at  several  places  in  the  road  high  up  on  the  ridges,  apparently  associated  with  the 
"E"  coal.  Southeast  of  Nashville,  on  the  road  toward  Gettysburg,  is  an  outcrop  near  the 
top  of  the  hill,  probably  at  the  horizon  of  the  "E"  coal.  The  clay  also  occurs  a  little  to 
the  northwest  or  north  of  Robertsville  within  one-half  mile  of  Little  Mahoning  Creek. 
Flint  clay  was  again  seen  near  Glen  Campbell,  on  the  road  from  Urey  to  Ridge  along  the 
crest  oi  the  hill,  and  on  the  south  side  of  Bear  Run  on  the  road  from  Glen  Campbell  to 
North  Summit 
SOFT  CLAYS. 
As  previously  stated,  practically  all  the  coal  beds  of  the  Allegheny  formation  are  under- 
lain by  beds  of  clay,  and  in  most  cases  the  flint  clays  noted  above  have  soft  clays  associated 
with  them.  Of  these  clays  the  bed  underlying  the  "B"  coal  appears  to  be  of  the  greatest 
thickness  and  probable  value.  The  "  B"  coal  is  above  drainage  along  most  of  the  valleys 
of  the  area  under  consideration,  except  those  lying  immediately  in  the  center  of  the  syn- 
clines.  Prospecting  would  doubtless  reveal  clays  of  commercial  thickness  and  quality  at 
the  horizon  of  the  other  coals,  but  as  a  rule  the  thickness  and  character  of  the  clays  are 
not  revealed  in  coal  mines.  Where  the  thickness  of  the  clay  associated  with  the  other 
coals  was  determined,  it  was  usually  found  to  be  not  over  2  feet.  The  quality  of  the  clay 
is  unknown 
SHALES. 
The  shales  of  the  eastern  portion  of  this  region  seem  to  be  uniformly  sandy,  though  pos- 
sibly not  too  much  so  for  the  successful  manufacture  of  brick  or  tile.  In  the  western  part 
of  Clearfield  County  and  the  northeastern  part  of  Indiana  County  there  are  many  places 
where  the  shales  immediately  over  the  Mahoning  sandstone  and  immediately  below  the 
"E"  coal  appear  to  be  less  sandy  in  character,  and  they  may  warrant  careful  testing  or 
experimental  work.  A  few  of  the  exposures  near  the  railroads  may  be  noted.  These 
shales  outcrop  between  the  "D"  and  "E"  coals  at  a  large  number  of  points  around  Glen 
Campbell.  A  short  distance  east  and  west  of  Burnside  the  shale  above  the  Mahoning  sand- 
stone occurs  from  100  to  150  feet  above  the  horizon  of  the  "D"  coal.  The  use  of  these 
shales  for  the  manufacture  of  paving  bricks  is  suggested.  Similar  shales  are  found  over  a 
broad  area  in  the  northern  part  of  this  county.  To  the  east  of  Rossiter  the  shales  between 
the  "E"  and  "D"  coals  seem  promising.  Conemaugh  shales  are  well  exposed  by  the  grad- 
ing for  the  Buffalo,  Rochester  and  Pittsburgh  Railway,  though  these  generally  seem  rather 
too  sandy  for  most  purposes.  Somewhat  similar  sandy  shales  are  being  successfully 
worked  at  Punxsutawney  on  a  small  scale,  being  made  into  common,  pressed,  and  paving 
brick.  A  somewhat  less  sandy  shale  occurs  just  south  of  Punxsutawney,  about  150  feet 
above  the  valley  floor. 
