GLASS-SAND    INDUSTRY    OF    INDIANA,   KENTUCKY,  AND    OHIO.        371 
stone,  and  the  limestone  phase  the  Lucas  limestone.  The  rocks 
are  covered  by- only  a  thin  veneer  of  drift,  a  few  inches  to  2  or  3  feet 
thick.  The  surface  of  the  country  is  flat  and  the  rocks  are  quarried 
from  two  large  pits  trending  north-south,  or  with  the  strike  of  the 
rocks.  The  beds  dip  about  5°  to  the  west,  the  sandstone  underlying 
the  dolomite  and  outcropping  on  the  east  of  it.  The  sandstone  quarry 
to  the  east  is  15  to  25  feet  deep  and  covers  about  2\  acres.  The 
dolomite  quarry  has  been  excavated  to  about  the  same  depth  and 
covers  about  twice  the  area  of  the  sand  quarry.  Numerous  springs 
emerge  near  the  bases  of  the  quarries  and  are  drained  by  ditches 
into  water  holes,  which  are  emptied  by  6-inch  pumps.  Between  the 
two  pits  stands  the  sand  mill,  with  its  necessary  trackage,  while  west 
of  the  dolomite  quarry  stands  a  mill  for  crushing  that  stone.  Both 
quarries  are  operated  on  the  same  plan.  The  sandstone  is  a  grayish 
to  white,  firm  rock,  in  thin  beds,  having  a  total  thickness  of  15  to  25 
feet.  At  the  base  of  the  sandstone  lies  a  conglomerate  of  dolomite 
pebbles  in  a  sandstone  matrix,  below  which  is  a  bed  of  hard,  fine- 
grained, dove-colored  dolomite  with  an  uneven  surface.  At  the  top 
the  sandstone  has  in  places  received  a  slight  yellowish  stain.  Its 
grains  are  rather  fine  and  under  a  field  lens  appear  to  be  clear  quartz, 
for  the  most  part  worn  smooth.  On  the  whole,  the  sand  is  a  very 
light-colored,  clean  material.  Compressed-air  drills  are  used,  and 
the  sand  is  blasted  and  loaded  into  trams  that  are  moved  by  gravity 
over  tracks  that  converge  at  a  turntable.  The  cars  are  drawn  up 
an  incline  by  cable  into  the  mill,  where  they  dump  into  a  Blake 
crusher.  When  crushed  the  sand  passes  through  three  sets  of  rolls 
is  washed  twice  by  the  " auger"  method,  is  screened,  dried  by  steam 
coils;  screened  again,  and  stored.  From  the  stock  house  the  sand  is 
delivered  through  pipes  into  cars.  This  company  owns  and  oper- 
ates its  railroad  into  Toledo.  The  output  of  sand  aggregates  80  tons 
a  week  and  it  is  shipped  for  glass  making  mainly  to  Ohio,  Indiana, 
and  Pennsylvania.    An  analysis  of  the  sandstone  is  given  on  page  376, 
The  dolomite  is  not  burned,  nor  sold  as  building  stone,  but  is  all 
crushed  and  used  as  fluxing  material. 
Holland. — Near  Holland  and  Monclova,  about  10  miles  west  of 
Toledo,  interbedded  sandstone  and  dolomite  of  the  Monroe  forma- 
tion lie  near  the  surface,  as  at  Sylvania.  About  2\  miles  south- 
west of  Holland  are  the  quarries  of  the  Ohio  Stone,  Cement,  and 
Construction  Company  and  of  the  Lake  Shore  and  Michigan  South- 
ern Railway  Company.  Both  quarries  produce  only  crushed  dolo- 
mite at  present,  although  about  fourteen  years  ago  glass  sand  was 
obtained  here,  crushed,  screened,  cleaned  by  fan  draft,  and  about 
1,000  cars  of  it  were  shipped  to  the  glass  factory  at  Maumee.     The 
