INVESTIGATIONS    OF    IRON    ORES,  ETC.  25 
letin.  The  more  detailed  of  these  studies  was  carried  on  for  the 
North  Carolina  Geological  Survey  and  is  presented  here  by  permission 
of  the  State  geologist. 
Graphite. — While  studying  the  iron  ores  of  Wyoming,  Mr.  Ball  pre- 
pared for  this  bulletin  a  brief  note  on  graphite  deposits  occurring  in 
the  same  area. 
Diatomaceous  earth. — Messrs.  Arnold  and  Anderson  have  prepared 
for  the  present  bulletin  a  comparatively  detailed  report  on  the 
extensive  deposits  of  diatomaceous  shale  which  occur  in  California. 
Mineral  paints. — During  the  last  year  several  mineral-paint  pro- 
ducing localities  have  been  visited  by  Survey  geologists,  and  in  this 
bulletin  a  statement  concerning  the  use  for  paint  of  the  Clinton  or 
oolitic  red  hematite  ores  is  presented  by  Mr.  Burchard. 
Phosphates  and  phosphorus. — Several  papers  included  in  the  present 
bulletin  deal  with  interesting  deposits  of  phosphates.  Mr.  Stose  de- 
scribes the  manufacture  of  phosphorus  from  mineral  materials,  while 
Professor  Purdue's  paper  takes  up  the  recently  discovered  phosphate 
fields  of  Arkansas.  The  paper  by  Messrs.  Weeks  and  Ferrier  describes 
a  new  and  important  phosphate  district  in  the  western  United  States. 
Sulphur. — A  brief  paper  on  some  Utah  sulphur  deposits,  by  W.  T. 
Lee,  will  be  found  in  the  present  bulletin.  So  far  no  detailed  study 
of  the  sulphur  and  pyrite  deposits  of  the  United  States  has  been 
taken  up  by  the  Survey,  though  such  an  investigation  and  report 
would  be  of  great  industrial  interest  and  value  and  should  receive 
consideration  in  the  near  future. 
