,    GLASS    SAND    OF    MIDDLE    MISSISSIPPI    BASIN.  467 
As  the  dip  of  the  formation  is  to  the  northeast,  the  overburden  presents  an  ever-increasing 
thickness  in  this  direction,  so  that  the  eastward  limit  of  profitable  quarrying  will  be  deter- 
mined largely  by  this  factor.  As  the  sandstone  in  the  upper  2.5  to  30  feet  is  slightly  colored , 
it  is  usually  kept  separate  from  the  whiter  material  below,  which  is  prepared  for  glas3  mak- 
ing: The  poorer  grade  of  sand,  after  being  crushed,  dried,  and  screened,  is  sold  mainly  to 
steel  foundries.  An  analysis  of  sand  prepared  for  glass  making  from  this  quarry  is  given 
on  page  456.  The  daily  output  from  this  plant  at  the  time  of  visit  was  about  16  cars  of  30 
tons  each. 
Becker. — At  Becker,  a  station  on  the  Chicago,  Rock  Island  and  Pacific  Railway,  on  the 
south  side  of  Missouri  River,  about  3  miles,  below  Klondike,  are  sand  quarries,  now  inactive, 
but  formerly  worked  by  the  Tavern  Rock  Sand  Company. 
Grays  Summit. — Nearly  a  mile  northeast  of  the  Missouri  Pacific  depot  at  Grays  Summit, 
and  6  miles  south-southeast  of  Klondike,  is  the  plant  of  the  White  Sand  Company  of  Mis- 
souri. Lying  nearly  in  strike  with  the  beds  at  Klondike,  the  St.  Peter  sandstone  is  here  at 
a  high  elevation  on  the  divide  between  the  Missouri  River  drainage  and  that  of  the  Meramec. 
The  quarries  of  this  company  are  located  on  the  southeastern  slope  of  the  divide  and  are 
connected  with  the  Missouri  Pacific  Railway  by  a  spur.  Seventy-five  to  80  feet  of  the  for- 
mation have  been  exposed  by  stripping  and  quarrying.  The  base  is  not  exposed,  but  the 
top  is  overlain  by  the  "First  Magnesian"  limestone.  A  total  thickness  of  167  feet  was 
reported  at  this  place,  based  on  the  measured  thickness  of  the  exposed  portion  plus  a  thick- 
ness noted  in  a  drill  hole.  While  the  actual  thickness  could  not  be  measured  at  the  time  of 
visit,  it  seems  rather  doubtful  that  the  thickness  of  the  formation  should  be  doubled  within 
6  miles.  However,  it  is  obviously  thicker  at  Grays  Summit  than  at  Klondike.  The  char- 
acter of  the  sand  shows  no  marked  variation  from  that  of  the  district  in  general.  The  color 
is  uniformly  white,  except  for  faintly  tinted  bands,  the  rock  from  which  is  easily  segregated 
and  run  separately  through  the  mill,  so  that  a  product  of  uniform  grade  is  insured.  Some 
small  lumps  of  iron  oxide  cementing  the  sand  into  concretions  occur,  but  these  are  easily 
removed  by  screening.  The  sand  is  crushed,  screened,  and  dried  at  this  plant.  The  prin- 
ciple of  operation  is  essentially  the  same  as  that  employed  at  Klondike,  but  there  are  differ- 
ences worth  noting.  After  being  "shot  "  down  the  sand  is  brought  by  tram  cars  to  a  30- 
inch  belt  conveyer,  which  carries  it  into  the  mill  on  a  level  with  the  base  of  the  quarry  and 
empties  it  into  a  crusher.  The  crusher  consists  of  thirty-two  20-pound  hammers  revolv- 
ing 1,000  times  per  minute.  A  wet  screen  intervenes  between  the  crusher  and  the  revolv- 
ing driers,  which  are  heated  directly  by  blast  from  coke  as  a  fuel.  After  drying,  the  sand 
is  once  more  screened  before  being  stored.  The  sand  from  this  plant  is  shipped  mainly  to 
glass  factories,  but  it  is  sold  for  all  other  purposes  for  which  sand  is  in  demand.  An  anal- 
ysis of  a  sample  of  crude  sand  from  this  plant  is  given  on  page  456. 
Pacific. — For  more  than  thirty  years  the  shipping  of  sand  has  been  one  of  the  leading 
industries  of  Pacific,  a  town  on  both  the  Frisco  and  the  Missouri  Pacific  railroads,  about  35 
miles  west  of  St.  Louis,  and  to  the  conspicuous  occurrence  of  the  St.  Peter  sandstone  at  this 
place  is  due  the  former  name,  ''Pacific"  sandstone.  From  beyond  the  western  boundary 
of  the  town  eastward  for  about  one-half  mile  the  sandstone  is  well  situated  for  quarrying  in 
the  bluff  along  the  northern  edge  of  the  Meramec  River  flood  plain.  It  ranges  from  about 
80  feet  above  the  flood  plain  on  the  west  to  about  50  feet  above  the  river  at  the  easternmost 
quarry.     Three  firms  are  now  producing  sand  at  Pacific. 
The  Pacific  White  Sand  Company  has  quarries,  not  now  in  operation,  just  north  of  the 
town,  and  its  main  active  quarry  is  about  1^  miles  east  of  the  town.  This  quarry,  on  the 
bank  of  Meramec  River,  discloses  massive  beds  of  sandstone  separated  by  distinct  bedding 
planes.  Along  one  such  plane  near  the  top  of  the  quarry  occurs  a  seam  of  yellowish  fir.e 
sandy  shale  one-fourth  to  one-half  inch  thick,  and  this  shale  appears  also  in  the  Frisco  Rail- 
road cut  north  of  the  quarry.  Shale  so  rarely  occurs  in  this  formation  that  its  presence 
here  is  worthy  of  note.  It  must  be  removed  in  the  preparation  of  high-grade  sand.  In 
color  the  sand  is  mostly  pure  white,  but  striking  variations  are  displayed,  including  shades 
of  pink,  light  yellow  to  dark  brown,  and  along  the  bedding  planes  near  the  thin  shale  the 
