472  CONTRIBUTIONS    TO   ECONOMIC    GEOLOGY,  1905. 
are  those  of  the  Elkader,  Waukon,  and  Richland  ('enter  quadrangles.  Tests  made  of  SJ 
Peter  sand  from  a  point  near  Grant  River  south  of  Flora,  Wis.,  indicate  that  its  quality- 
is  all  that  could  be  desired  as  a  glass  material.     (See  No.  10,  pp.  462-463.) 
In  the  valley  of  Wisconsin  River  the  "Potsdam"  formation  contains  several  valuable 
beds  of  clean  quartz  sand,  rather  coarse,  well  rounded,  and  loosely  cemented.  Exposure* 
probably  of  the  "Jordan"  sandstone  horizon,  occur  in  the  bluffs  near  Boscobel,  Wis.,  m 
close  proximity  to  the  Chicago,  Milwaukee  and  St.  Paul  Railway.  The  properties  of  sand 
from  this  locality  are  given  under  No.  11  (pp.  462-463).  The  chemical  composition  is 
excellent  and  the  sand  is  of  very  desirable  size. 
GENERAL  ASPECTS   OF   GLASS-SAND   INDUSTRY. 
The  consumption  of  glass  sand  has  been  rapidly  increasing  for  many  years,  and  it  is 
probable  that  it  will  continue  to  do  so  indefinitely.  Vast  resources  of  the  material  are  in 
sight.  The  uses  for  glass  are  now  so  varied  and  extensive  that  it  may  well  be  classed  with 
iron  and  cement  in  its  importance  under  present  conditions.  Glass  sand  in  situ  possesses 
relatively  little  intrinsic  value.  The  market  value  is  due  to  the  labor  cost  of  extraction 
and  preparation. 
The  factors  on  which  a  deposit  of  sand  depends  for  its  possible  value  for  glass  making 
are  (1)  chemical  composition,  (2)  physical  character,  (3)  amount  available,  (1)  location 
with  respect  to  fuel  supplies,  (5)  conditions  of  quarrying  or  mining,  (6)  location  with 
respect  to  transportation  routes,  and  (7)  location  with  respect  to  markets.  The  first  two 
have  been  treated  rather  fully  in  the  foregoing  pages. 
A  deposit  so  thin  as  20  feet  should  have  an  area!  extent  of  at  least  20  acres  of  good  sand  in 
sight  to  warrant  the  erection  of  a  mill  and  trackage.  Most  deposits  are  thicker  than  20 
feet,  but  it  would  be  safer  to  have  a  much  higher  ratio  between  area!  extent  and  thickness 
than  the  minimum  given.  Where  ledges  of  sand  require  stripping  of  overlying  limestone, 
the  limestone  may  in  certain  cases  l>c  of  such  purity  that  it  also  could  be  used  for  glass 
making;  if  this  is  not  the  case  other  uses  should  be  sought  for  it  as  a  by  product.  In 
regard  to  fuel,  every  plant  turning  out  glass  sand  in  quantity  sufficient  to  net  a  profit  must 
be  equipped  with  power  for  moving  the  sand  and  drying  it,  and  in  most  cases  with  equip- 
ment   lor  cleaning  it    as  well.      The   margin   of   prolil    is  at    present    so  low   that    the  cost    of 
preparation  cannot  reasonably  stand  freight  charges  on  coal  for  more  than  50  miles. 
Natural  gas  would  be  a  suitable  fuel,  especially  in  the  operation  of  rotary  driers.  In  respect 
to  transportation  routes,  the  general  principle  "the  more  available  the  better"  is  applicable. 
Aside  from  the  necessity  of  securing  fair  and  uniform  freight  rates  experience  has  shown, 
especially  where  the  dependence  is  on  only  one  railroad  for  transportation,  that  shortness 
of  cars  at  certain  season-  may  seriously  handicap  a  plant  in  its  shipments  and  lead  to  cancel 
lation  of  many  orders.  In  respect  to  markets,  it  must  be  considered  thai  sand  is  for  its 
value  one  of  the  bulkiest  products,  and  therefore  one  whose  < lost  to  the  consumer  is  great  Iv 
influenced  by  distance.  At  the  same  time  the  question  of  permanence  of  these  markets 
must  be  considered. 
Some  of  the  huge  sand  properties,  together  with  their  mills,  represent  an  outlay  of  about 
$75,000,  a  sum  that  requires  good  l>usme>s  judgment  for  its  investment  and  subsequent 
careful  management  in  order  to  keep  it  paying  adequate  interest.  Strong  competition  in 
the  Middle  State-  has  forced  prices  down  very  low  at  present,  and  competition  in  the  form 
of  the  small  producer  who  leases  a  sand  bank  and  works  out  by  hand  and  team  all  the 
choice  sand  within  convenient  distance  and  then  abandons  the  quarry,  having  figured 
only  daily  wages  to  himself  as  profit,  has  resulted  m  some  embarrassment  to  the  larger 
companies. 
