INVESTIGATIONS   OF    METALLIFEROUS    ORES.  17 
carrying  wolfram,  or  the  tungstate  of  iron,  which  now  constitute  one 
of  the  most  important  sources  of  tungsten  in  this  country. 
In  the  course  of  an  areal  survey  of  the  coal  lands  to  be  rendered 
available  by  the  new  Moffat  railroad,  in  and  about  the  valleys  of  the 
White  and  Yampa  rivers,  Hoyt  S.  Gaie  has  examined  some  new 
deposits  of  the  uranium-  and  vanadium-bearing  mineral,  carnotite, 
which  occur  in  the  upturned  Dakota  sandstones  east  of  the  coal 
basins  in  Rio  Blanco  County.  These  deposits  are  extremely  impor- 
tant as  a  further  possible  source  of  the  new  metal,  radium.  Brief 
reports  giving  the  results  of  the  three  reconnaissances  mentioned 
above  are  included  in  this  bulletin. 
MONTANA. 
An  areal  geological  survey  of  the  Philipsburg  quadrangle,  which 
covers  30  minutes  of  latitude  and  longitude,  has  bee_i  carried  on  dur- 
ing the  last  summer  under  the  direction  of  F.  C.  Calkins.  W.  H.  Em- 
•  mons  was  detailed  to  make  an  economic  examination  of  this  area, 
which  contains  numerous  important  ore  deposits.  During  the  sum- 
mer he  completed  a  field  study  of  the  two  most  important  deposits 
of  the  region — that  worked  by  the  Granite-Bimetallic  mine,  which  is 
a  typical  vein  deposit,  producing  silver,  and  that  worked  by  the 
Cable  mine,  which  is  an  auriferous  contact  deposit  in  limestone  sur- 
rounded by  granite.  A  preliminary  report  on  these  two  mines  is 
given  in  this  bulletin. 
NEVADA. 
Early  in  the  summer  the  writer  visited  the  new  copper  district  at 
Ely,  Nev.,  which  promises  to  become  one  of  the  greatest  producers  of 
copper  in  that  portion  of  the  country.  A  railroad  140  miles  long  was 
building  to  develop  the  district,  and  large  concentrating  and  smelting 
plants  were  planned  to  treat  the  low-grade  disseminated  copper  ores 
in  porphyry  that  have  been  proved  to  exist  there  in  large  quantities. 
Preliminary  geological  reports  on  the  district  have  already  been  pub- 
lished in  a  scientific  periodical,  and  the  writer's  visit  was  made  simply 
to  determine  the  area  that  should  be  included  in  a  topographical  map 
that  will  serve  as  a  basis  for  the  special  geological  study  of  the  district. 
The  topographical  survey  has  since  been  completed,  and  it  is  hoped 
that  it  will  be  possible  during  the  coming  season,  when  the  mines  shall 
be  actually  working,  to  make  an  exhaustive  examination  of  the  geol- 
ogy and  ore  deposits  of  the  district. 
It  has  been  planned  that  Mr.  Ransome  should  make  a  final  exam- 
ination of  the  Goldfield,  Bullfrog,  Rhyolite,  and  neighboring  districts  in 
southwestern  Nevada,  in  the  light  of  the  latest  mining  developments, 
before  publishing  his  report  on  this  region.     When  it  was  learned  that 
Bull.  315—07 2 
