1(')S  CONTRIBUTIONS    TO    ECONOMIC    GEOLOGY,  1903.  [bull. 225. 
Analyses  of  Brookville  clay. 
SiO,  — . 
A1A— 
Fe203  .- 
FeO.... 
Mn02  -. 
CaO .... 
MgO... 
Alkalies 
H20,  Or^ 
Per  cent. 
45.  45 
36. 125 
Per  cent. 
62.05 
27.71 
2.275 
.60 
.168 
.15 
.342 
.20 
1.29 
2.40 
13.73 
6.67 
99.  380 
99.78 
1.  Roaring  Run,  three-fourths  mile  west  of  Woodland  Station.     Bed,  4  to  5  feet;  hard  clay.     Second 
Geol.  Surv.  Pennsylvania,  Rept.  H,  p.  123.    S.  A.  Ford,  analyst. 
2.  From  Haydenville  Mining  and  Manufacturing  Company,  Haydenville,  Ohio.    Geol.  Surv.  Ohio, 
vol.  7,  p.  139.  *  E.  M.  Reed,  analyst. 
At  Haydenville  this  clay  is  made  into  paving  bricks,  fireproofing, 
and  sewer  pipe.  The  Brookville  clay  has  been  mined  for  thirty-five 
years  in  Indiana  County,  where  it  is  a  plastic  clay  of  good  quality, 
varying  in  thickness  from  3  to  11  feet.  It  contains,  however,  many 
iron  balls  and  has  to  be  hand  picked.®  In  Fayette  County,  also,  where 
it  is  a  flint  clay  of  excellent  quality,  it  has  been  extensively  used  for 
refractory  materials.6  At  the  typical  locality  of  the  overlying  coal, 
Brookville,  Jefferson  County,  the  clay  beneath  is  15  feet  thick,  but  only 
the  upper  6  feet  are  used.c  It  seems,  then,  that  the  Brookville  horizon 
in  Beaver  County  may  yet  become  a  producer  of  good  clay  where  the 
bed  can  be  profitably  mined.  South  of  Beaver  Falls  it  could  be  reached 
only  by  shaft,  except  at  the  locality  noted  at  the  mouth  of  Brady s  Run. 
Clarion  day. — This  bed  underlies  the  Clarion  coal,  and  is  exposed 
opposite  Fallston,  on  Bradys  Run,  where  it  has  been  opened  by  the 
Fallston  Pottery  Company  by  a  drift  150  feet  long.  The  cla}^  appears 
to  be  of  uniform  thickness  and  character,  but  it  is  not  now  used.  It 
has  been  variously  reported  as  6,  10,  and  12  feet  thick,  with  no  coal 
above;  only  contradictory  reports  of  its  quality  could  be  obtained. 
It  is  exposed  east  of  New  Brighton  on  Blockhouse  Run,  above  the 
Sherwood  pottery;  above  New  Brighton,  on  the  railroad,  where  it  is 
'S  or  1  feet  thick;  and,  Hopkins  reports,  in  Paved  Run,  but  it  has  not 
been  worked  in  any  of  these  places.  It  is  further  exposed  in  the 
ravines  along  the  railroad  south  of  Beaver  Falls,  and  thence  runs 
under  Beaver  Falls  terrace. 
a  Prof.  Paper  U.  S.  Geol.  Survey  No.  11,  p.  218. 
b(  teologic  Atlas  U.  S.,  Folio  82,  U.  S.  Geological  Survey,  p.  20. 
c  Second  Geol.  Surv.  Pennsylvania,  Report  H,  p.  225. 
