1,000

5,000

1890  ..
2,632

50,240

1884..
1,000

5,000

1891.
21,988

1885..
1,000

5,000

1892  ..
43,655

1886..
1,200

6,000

1893  ..
22,582

BUHR-8TONE8.  255


GRINDSTONES.
This  is  a  fine-grained  sandstone  differing  greatly  in  texture
and  hardness  in  different  localities.  The  principal  source  of
grindstones  in  the  United  States  is  the  geological  formation
known  as  the  Berea  Grit,  which  underlies  large  areas  in  the
northeastern  part  of  Ohio.  Near  Grindstone  City,  Michigan,
there  is  found  a  fine-grained  argillaceous  stone,  of  a  uniform
blue  color,  which  is  in  general  use  for  finishing  work,  especi-
ally where  a  very  fine  edge  is  required.  Near  Marquette,  on
the  shore  of  Lake  Superior,  the  writer  discovered  a  large
quantity  of  an  exceedingly  fine-grained  silicious  sandstone  of
close  texture,  and  had  some  of  it  worked  up  in  Ohio,  where  it
was  made  into  small  stones  of  excellent  cutting  power,  and  it
is  probable  that  as  soon  as  arrangements  can  be  made  the
material  will  be  more  extensively  tried.  In  1884  the  total
imports,  finished  and  rough,  were  7056  tons,  valued  at  $86,286.
The  home  production  in  1893  was  valued  at  $338,787,  while
the  imports  were  $59,569.
BUHR-STONES.
The  leading  localities  for  this  stone  in  the  United  States  are
Ulster  Co.,  New  York,  where  the  stone  known  as  Esopus  stone
is  a  quarizite  of  variable  texture  and  hardness ;  Lancaster  Co.,
Pennsylvania,  here  called  the  Cocalico,  a  conglomerate  stone
foand  as  bowlders  scattered  over  the  surface ;  Peninsula,  Sum-
mit Co.,  Ohio,  where  a  white  variety  of  the  Berea  Grit  is
wori^ed,  mainly  for  the  purpose  of  grinding  oatmeal  and  bar-
ley.    Kany  other  places  have  reported  discoveries  of  bahr-


256  MINERALS,  MINES,  AND   MINING.
