378  CONTRIBUTIONS    TO    ECONOMIC    GEOLOGY,  1906,  PAKT    I. 
sand,  with  an  admixture  of  the  red  loam,  is  shipped  in  large  quanti- 
ties to  mills  at  Birmingham,  Bessemer,  Ensley,  and  New  Decatur, 
Ala.,  where  it  is  used  for  molding  purposes. 
At  North  Birmingham  the  Lookout  sandstone,  of  early  Pennsyl- 
vanian  age,  is  quarried  for  sand-lime  brick  making.  Certain  beds  of  i 
this  sandstone  might  prove  pure  enough  for  glass.  The  rock  is  of 
coarser  grain  than  the  "Oxmoor,"  but  is  very  firmly  cemented  and  is 
consequently  harder  to  crush.  Its  chemical  composition  is  shown  on 
page  382. 
Arkansas. — Attention  was  called  in  an  earlier  paper  a  to  deposits 
of  glass  sand  of  excellent  grade  on  White  River,  in  northern  Arkansas. 
These  are  practically  inexhaustible  and  of  the  same  age  (Ordovician, 
St.  Peter  formation)  as  the  great  Pacific,  Missouri,  and  Fox  River,  Illi- 
nois, deposits.  It  is  of  interest  to  note  that  near  Guyon,  on  the  White 
River  branch  of  the  Missouri  Pacific  Railroad  the  exploitation  of  these 
deposits  has  recently  been  undertaken,  and  it  is  reported  that  the 
glass  sand  is  to  be  used  for  flint,  window,  and  bottle  glass  at  Coffey- 
ville,  Kans.      (See  p.  382  for  analyses.) 
Georgia. — The  rare  use  of  a  river  sand  for  glass  making  is  reported 
from  Augusta,  Ga.  Sand  obtained  along  Savannah  River  is  shipped 
to  Chattanooga,  Tenn.,  where  bottles  are  successfully  made  from  it. 
The  sand  is  composed  of  fine  to  coarse  angular  grains  of  quartz,  both 
clear  and  milky  varieties  being  present.  In  mass  it  has  a  light  gray 
or  dingy  white  color. 
Florida. — The  unusual  cleanness  and  even  grain  of  the  Gulf  beach 
sand  at  Pensacola,  Fla.,  suggested  to  the  writer  its  suitability  for 
glass  making,  and  analysis  of  this  sand  (see  p.  382)  shows  that  it  pos- 
sesses the  requisite  purity.  The  sand  is  slightly  coarse,  the  greater 
part  of  it  passing  a  20-mesh  sieve,  but  not  40-mesh.  Although  at 
present  remote  from  any  glass-making  centers,  the  deposit  is  not  far 
from  lines  of  rail  and  water  transportation. 
Iowa. — The  Potsdam  sandstone  (Cambrian)  and  the  St.  Peter  sand- 
stone (Ordovician)  occurring  along  Mississippi  River  in  northeastern 
Iowa  have  already  been  mentioned  as  available  glass-making  mate- 
rials.6 In  addition,  it  is  now  possible  to  give  certain  information 
concerning  the  Dakota  sandstone  (Cretaceous)  in  the  northwestern 
part  of  the  State.  This  rock  has  been  found  in  quantity  and  purity 
sufficient  to  make  it  a  possible  source  of  sand  for  making  bottle  glass. 
It  outcrops  in  bluffs  along  Floyd  River  valley  northeast  of  Sioux 
City  and  has  been  quarried  for  building  and  molding  sand  near  the 
a  Burchard,  E.  F.,  Glass  sands  of  the  middle  Mississippi  basin:  Bull.  U.  S.  Geoi.  Survey  No.  285, 1906, 
p.  470. 
b  Burchard,  E.  i\,  ibid.,  p.  471. 
