474  CONTRIBUTIONS    TO    ECONOMIC    GEOLOGY,  190",. 
About  150  feet  of  rock  are  exposed  in  the  quarry  and  most  of  this  is  available  for  glass 
sand.  The  total  thickness  of  the  formation  is  probably  about  170  or  180  feet.  The  upper 
part  is  a  hard  bed  20  feet  thick  which  is  not  mined,  but  is  used  as  the  east  wall  of  the  hole. 
On  account  of  the  steep  eastward  dip  it  overhangs  and  is  to  some  extent  a  source  of  danger, 
as  in  places  it  has  caved  in.  The  sandstone  as  quarried  varies  from  pure  white  to  creamy  and 
is  generally  fine  grained  with  an  occasional  coarse  bed.  Below  the  surface  it  crumbles  on 
being  quarried  and  the  sand  is  handled  largely  by  shovel.  Large  lumps  are  readily  broken 
with  a  sledge  hammer,  and  the  few  masses  from  harder  beds  which  do  not  yield  to  this  treats 
menl  are  thrown  aside  and  not  utilized,  as  this  company  does  not  use  a  rock  crusher.  The 
rock  is  drilled  by  steam,  the  power  plain  being  located  on  the  old  floor  of  the  quarry  on  the 
level  of  the  tramway  tunnel.  The  quarry  has  since  been  carried  30  feet  below  this  level] 
which  necessitates  a  cable  tram  to  haul  the  loaded  cars  to  the  grade  of  the  tunnel.  On 
account  of  the  inclosed  character  and  the  depth  of  the  quarry  the  heat  becomes  unendurable 
in  the  summer,  and  a  canvas  awning  is  suspended  over  the  workmen  to  shield  them  from  the 
sun. 
From  the  mouth  of  the  tunnel  '200  feet  above  the  railroad  a  narrow-gage  railroad  runs  to 
the  mill  at  the  river,  three-fourths  of  a  mile  north.  The  grade  on  this  tramway  is  suffi- 
ciently gentle  for  mules  to  haul  the  empty  cars  over  it.  but  recently  a  small  locomo- 
tive was  installed.  At  the  mill  the  sand  and  rock  are  passed  through  a  roller  or  mull  and 
then  washed  and  dried,  the  product  being  a  pure  white  quartz  sand,  suitable  for  making 
table,  window,  and  plate  glass.  The  capacity  was  reported  to  be  200  tons  a  day.  The  mill 
was  destroyed  by  (ire  early  in  lOOo,  but  has  since  been  rebuilt. 
The  other  mines  on  this  ridge  are  all  located  on  the  eastern  flank  along  the  Warm  Spring 
Valley.  The  construction  of  the  Berkeley  Springs  Branch  of  the  Baltimore  and  Ohio  Kail- 
road  from  Hancock  to  Berkeley  Springs  made  the  eastern  pari  of  the  Warm  Spring  Ridge 
accessible  to  the  railroad  and  was  the  cause  of  the  recent  rapid  development  of  the  mining 
industry.  Two  com  panics  began  operation  about  the  same  time,  the  Berkeley  Springs  Sand 
Company  and  the  West  Virginia  Sand  Company. 
Berkeley  Springs  Stun/  Company.  This  company  opened  a  mine  at  the  northern  edge  of 
the  town  of  Berkeley  Springs.  This  is  t he  .southernmost  openingon  the  ridge.  The  quarry, 
like  all  those  on  the  eastern  side  of  the  ridge,  is  midway  on  the  slope,  aboui  150  feet  above  the 
valley  bottom,  and  near  the  base  of  the  sandstone  exposure.  It  is  an  open  cut  200  feet  long 
bylOOfeel  across  and  50  or  60  feel  deep.  It  is  entered  by  a  shorl  tunnel  through  the  harder 
cap  rock  forming  the  eastern  face,  which  is  not  quarried  here.  The  rock  appears  to  be  of 
excellent  quality  and  has  furnished  a  high  grade  of  sand.  A  cable  tramway  leads  to  the  mill 
in  the  valley.  The  mine  was  shut  down  during  the  writer's  visit  in  1001,  and  its  capacity 
was  not  determined. 
West  Vinj'inia  Sand  Company . — The  first  mine  operated  by  this  company  is  located  one- 
half  mile  north  of  the  quarry  of  the  Berkeley  Springs  Sand  Company.  In  1904  it  opened  a 
second  quarry  and  mill,  adjoining  the  first.  These  quarries  are  200  feet  above  the  valley*. 
The  older  opening  was  about  100  feet  square,  exposing  throughout  white  rock  somewhat 
harder  than  that  at  the  Pennsylvania  Company's  mine.  The  cap  rock  is  hard,  coarse,  and 
-omewhat  impure,  but  is  mined  and,  together  with  10  feet  of  surface  stripping  and  weathered 
streaks  where  the  sand  is  stained  yellowish,  makes  a  second  grade  of  sand,  used  for  bottle 
glass  and  railroad  sand.  Ninety  per  cent  of  the  rock  produces  sand  of  No.  1  grade,  pure 
white,  and  containing  over  98  per  cent  of  Si02.  This  is  used  for  plate  and  w  indow  glass  and 
tableware.  The  very  choicest  is  reported  to  run  99.8  per  cent  Si()_,  and  is  used  for  the 
finest  cut  glass. 
The  stone  is  drilled  by  compressed  air  and  is  brought  to  the  mills  in  the  valley  by  two 
double-track  gravity  cable  tramways.  The  material  is  assorted  at  the  quarries  and  the  sur- 
face rock  and  other  second-grade  material  is  sent  to  the  old  mill  for  treatment.  The  better 
grade  rock  is  taken  to  the  new  mill  on  elevated  tracks  and  dumped  into  chutes  which  lead 
directly  to  two  mulls,  the  larger  fragments  being  first  sorted  out  and  run  through  a  Blake 
crusher.     In  the  mulls,  which  are  circular  vats  in  which  revolve  two  heavy  iron  wheels  at, 
