24  CONTRIBUTIONS    TO    ECONOMIC    GEOLOGY,  1005. 
Gypsum.— In  the  course  of  Survey  work  in  the  Western  States  a  certain  amount  of 
data  on  their  gypsum  deposits  have  been  collected.  The  present  bulletin  contains  a  brief 
report  by  Mr.  C.  E.  Siebenthal  on  the  gypsum  of  the  Laramie  district  of  Wyoming. 
Stone. — Two  important  pieces  of  work  on  the  building  stones  of  the  United  States  were 
taken  up  in  1005  by  the  Survey.  The  first  was  the  preparation,  by  Prof.  T.  Nelson  Dale, 
of  a  report  on  the  "Slate  Deposits  of  the  United  States."  This  is  now  in  press  and  will 
be  published  in  1006  as  Survey  Bulletin  No.  275. 
Professor  Dale  also  commenced  work  on  the  granite  deposits  of  eastern  United  SI  ales. 
During  1005  he  made  a  very  careful  examination  of  all  the  Maine  granite  districts,  and 
his  report  on  that  State  will  be  submitted  before  the  close  of  1000. 
An  event  of  great  interest  to  the  stone  industry  is  described  briefly  in  Professor  Dale's 
paper  on  "A  New  Deposit  of  Slate  in  Maine,"  published  in  this  bulletin.  In  the  course 
of  his  geologic  work  in  Maine,  Professor  Dale  examined  a  bed  of  roofing  slate  wes!  of  the 
Monson  area  and  well  located  with  regard  to  new  transportation  routes.  Laboratory  tests 
and  careful  microscopic  work  prove  that  the  slate  is  of  fine  quality,  and  it  is  probable 
that  a  new  slate  district  of  considerable  importance  will  result  from  this  discovery. 
MISCELLANEOUS    NONMETALS. 
Glass  sand. — The  glass-making  materials  of  several  areas  were  studied  by  Survey  gcolo- 
gists  during  the  past  year,  and  the  present  bulletin  contains  three  reports  summarizing 
the  principal  points  brought  out  by  their  investigations.  Mr.  Burchard's  paper  on  the  glass 
sands  of  the  middle  Mississippi  basin  covers  an  area  of  particular  importance  to  the  glass 
industry-  In  the  course  of  this  work  Mr.  Burchard  carried  out  chemical  and  physical  tests, 
not  i >nly  of  glass  sands  now  in  use,  but  of  sands  which  seemed  to  be  worthy  of  atten- 
tion for  this  purpose.  The  subject  is  one  of  interest,  and  work  on  il  will  be  continued 
during  1006. 
Graphite. — A  report  on  the  graphite  deposits  of  Maine,  by  Mr.  (I.  O.  Smith,  appears  in 
this  bulletin.  In  addition  to  its  geologic  and  industrial  value,  this  report  is  notable  as 
containing  reference  to  a  new  method  for  obtaining  information  as  to  the  concentrating 
possibilities  of  any  given  graphite  in  advance  of  an  actual  mill  test.  Mr.  Smith  applied 
microscopic  methods,  and  has  determined  the  sizes  to  which  the  products  must  be  reduced 
before  satisfactory  separation  of  the  graphite  will  be  possible. 
Pyrite. — In  connection  with  his  work  on  the  copper  deposits  of  the  Appalachian  dis- 
trict Mr.  Walter  Harvey  Weed  examined  a  number  of  pyrite  deposits  which  are  likely  to 
prove  of  value  for  their  sulphur  content  rather  than  as  copper  ores.  A  report  on  these 
deposits  will  be  published  later. 
Phosphates. — During  the  last  two  years  interesting  developments  have  occurred  in  the 
phosphate  industry,  discoveries  of  value  having  been  made  in  Idaho  and  Utah.  It  was 
impracticable  to  place  Survey  geologists  in  these  new  districts  in  1005,  but  it  is  hoped 
that  examinations  can  be  made  during  1006. 
