CEMENTS. 
During  the  field  season  of  1903  most  of  the  cement-producing  dis- 
tricts of  the  United  States  were  visited,  data  being  collected  for  a 
report  on  the  cement  resources  and  industry  of  the  United  States,  to 
be  issued  as  a  Survey  bulletin.  The  districts  not  visited  in  1903  will 
be  taken  up  early  in  190-1,  and  a  detailed  report  on  the  subject  will  be 
published  as  soon  as  possible.  The  papers  presented  below  cover 
three  interesting  districts,  one  of  which  now  produces  about  60  per 
cent  of  the  total  annual  United  States  production  of  Portland  cement, 
while  the  other  two,  but  siightly  developed  at  present,  give  promise 
of  becoming  very  important  factors  in  the  cement  situation  in  the  near 
future. 
Pure  limestones  in  Pennsylvania  and  West  Virginia,  suitable  for 
Portland-cement  manufacture,  will  also  be  found  described  on  pp. 
516-517;  while  California  cement  materials  are  noted  on  pp.  176-177. 
THE  CEMENT  RESOURCES  OF  ALABAMA, 
By  Eugene  A.  Smith. 
In  Alabama  is  found  an  extensive  series  of  limestones  capable  of 
furnishing  excellent  raw  material  for  the  manufacture  of  Portland 
cement,  while  the  shales  and  cla}^s  necessary  to  complete  the  mixture 
are  found  in  every  county  in  the  State.  As  a  matter  of  convenience, 
the  Portland  cement  materials  of  northern  Alabama  and  of  central 
and  southern  Alabama  will  be  discussed  separately,  because  there  is 
a  marked  geologic  as  well  as  geographic  distinction  between  the  two 
portions  of  the  State. 
PORTLAND  CEMENT  MATERIALS  OF  NORTHERN  ALABAMA. 
The  raw  materials  for  the  manufacture  of  Portland  cement  occurring 
in  the  Paleozoic  formations  of  northern  Alabama  are  limestones,  shales, 
and  clays.  Of  these  the  limestones  belong  mainly  to  the  lower  Car- 
boniferous and  the  Trenton  formations;  the  shales  to  the  Coal  Meas- 
ures, and  the  clays  to  the  Cambrian,  lower  Carboniferous,  and  Coal 
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