CLAYS    AND    SHALES    IN    CLARION    COUNTY,  PA.  337 
ping.  Whether  the  lower  seam  is  a  split  from  the  upper  or  an  extra 
peam  is  uncertain.  The  lower  coal  lies  from  4  to  17  feet,  and  in  some 
places  perhaps  more,  below  the  upper.  The  lower  bed  appears  to 
be.  coterminous  with  the  flint  clay  of  this  horizon,  as  the  coal  was  not 
Identified  at  any  locality  outside  of  the  boundaries  of  the  area  occu- 
pied by  the  flint  clay. 
SHALES. 
The  only  shale  now  in  use  in  the  area  is  the  one  below  the  horizon 
lof  the  Clarion  coal.  This  shale  is  exposed  in  the  pit  of  the  Canton 
Tile  Hollow  Brick  Works,  west  of  New  Bethlehem,  described  below. 
|Other  deposits  of  shale  that  are  accessible  to  railroads  were  noted  as 
follows: 
At  the  railroad  crossing  between  Fairmount  and  Hawthorn;  thickness  30±  feet. 
I     In  hill  above  Underwood  mine  at  Ore  Bank  station,  on  the  Sligo  Branch  of  the 
Pennsylvania  Railroad;  thickness  50±  feet. 
In  hill  above  Baldauf  No.  1  mine,  on  a  branch  of  the  Pittsburg,  Summerville,  and 
Clarion  Railroad;  thickness  30±  feet. 
The  exposures  just  mentioned  are  typical  and  are  readily  accessible 
for  examination.  In  general,  however,  smaller  but  numerous  and 
widely  scattered  outcrops  indicate  that  a  considerable  thickness  of 
shale  lies  nearly  everywhere  above  the  Lower  Kittanning  coal. 
PLASTIC    CLAYS. 
Mercer  horizon. — Beds  at  the  horizon  of  the  Mercer  shale  outcrop 
above  drainage  level  along  Clarion  River,  in  the  lower  portion  of 
Leatherwood  Run,  at  Sligo,  and  just  west  of  Mayport,  but  no  good 
exposure  of  clay  was  noted  at  this  horizon  except  small  exposures  at 
Mayport. 
Brookville  horizon. — The  clay  at  this  horizon  was  seen  at  only  a  few 
places  and  probably  is  not  important. 
Clarion  horizon. — In  some  parts  of  the  quadrangle  there  are  two 
coals  and  two  accompanying  clays  at  the  horizon  of  the  Clarion  coal. 
A  section  in  a  run  near  the  schoolhouse,  about  1  mile  northeast  of  the 
Zion  churches,  shows  5  feet  or  more  of  white  clay  below  each  of  the  two 
coals.  At  the  road  fork,  one-half  mile  south  of  Rockville,  a  15-foot 
bed  of  clay  is  exposed  beneath  a  coal  blossom,  probably  Clarion.  On 
Leisure  Run,  4^  miles  north  of  New  Bethlehem,  10  feet  of  the  same 
clay  shows  above  the  run  and  below  a  16-inch  coal  blossom.  In  the 
vicinity  of  New  Bethlehem  this  clay  is  now  used  in  connection  with 
the  overlying  shale  by  the  Canton  Tile  Hollow  Brick  Company  in  the 
manufacture  of  hollow  building  brick  and  drain  tile. 
