478  CONTRIBUTIONS    TO    ECONOMIC    GEOLOGY,   1903.  [bull.  225. 
tions  under  various  firms  until  1890,  when  it  was  absorbed  by  the 
Pittsburg  (  lav  Manufacturing  Company.  This  company  still  operates 
the  works  together  with  the  New  Brighton  pottery,  which  is  also  an 
outgrowth  of  the  small  pottery  started  by  Elverson.  a 
In  1878  and  1879  Sherwood  Bros,  laid  the  foundation  of  the  present 
large  pottery  on  Blockhouse  Run.  They  started  with  one  kiln  and 
one  small  building,  enlarging  their  facilities  from  time  to  time  until 
now  this  company  is  one  of  the  most  progressive  in  Beaver  County  in 
the  production  of  high-grade  ware.  Their  specialties  are  glazed  milk 
pans,  stew  pans,  fruit  jars,  and  Bristol  ware.  Since  1880  the  follow- 
ing companies  have  been  established:  The  Enterprise  Pottery  and  the 
American  Porcelain  Company  on  Blockhouse  Run,  the  Mayer  Pottery 
Company  at  Beaver  Falls,  the  Fallston  Pottery  Company  on  Brady s 
Run,  and  Keystone  Pottery  at  Rochester.  Their  products  are  pitchers, 
toilet  sets,  plain  and  decorated  table  ware,  bath  tubs,  sinks,  jars,  jugs, 
cuspidors,  pots,  etc.  All  of  these  companies  use  the  Lower  Kittanning 
clay  in  varying  proportions,  combined  with  imported  clays  of  higher 
quality.  Flower  pots  are  manufactured  from  a  mixture  of  Lower  Kit- 
tanning  and  terrace  clays  at  Oak  Hill  pottery,  situated  north  of  New 
Brighton,  on  the  highest  terrace. 
Tiles.- — The  Beaver  Falls  Art  Tile  Company,  which  began  operations 
in  1887,  make  chieity  decorative  and  glazed  tile  of  great  variety  in  size 
and  color.  Eighty-live  per  cent  of  the  clay  used  is  taken  from  the 
Lower  Kittanning  clay  bed  on  Blockhouse  Run.  The  rest  of  the  clay 
is  imported.  The  ware  is  all  burned  in  saggers  made  from  Lower 
Kittanning  clay.  b 
Sewer  pipe. — The  manufacture  of  sewer  pipe  was  begun  in  1887  by 
the  Pittsburg  Sewer  Pipe  Company  on  Blockhouse  Run.  After  many 
changes  in  the  management  this  company  was  absorbed  in  1890  by  the 
Pittsburg  Cla}r  Manufacturing  Company. c  Sewer  pipe  requires  a  low- 
grade  siliceous  clay,  such  as  is  used  for  paving  brick.  This  is  obtained 
from  the  Lower  Kittanning  and  Lower  Freeport  beds,  though  the  latter 
is  not  now  worked. 
Refractory  materials.- — These  require  a  high-grade  clay  in  point  of 
fusibility.  The  Lower  Kittanning  clay,  Avhile  of  excellent  refractory 
quality,  can  not  be  used  alone  for  the  most  highly  refractory  products. 
To  supply  this  need,  flint  clay  is  imported  from  Cambria,  Clearfield, 
and  Clarion  counties.  When  this  is  mixed  with  the  Lower  Kittanning 
clay  it  gives  a  highly  refractory  material,  sufficiently  plastic  to  serve 
as  a  bond  for  the  flint  clay.  The  aim  is  to  obtain  a  mixture  as  siliceous 
as  possible,  which  will  at  the  same  time  develop  plasticity  well,  for  the 
more  siliceous  a  clay  is  the  less  it  shrinks  and  the  more  refractory  it 
becomes. 
"Hopkins,  T.  C,  op.  cit.,  p.  38.  l> Ibid,  p.  47.  c  Ibid,  p.  41. 
