NOTES    ON    ORE    DEPOSITS    OF    SOUTHWESTERN 
NEVADA  AND  EASTERN  CALIFORNIA. 
By  Sydney   H.  Ball. 
INTRODUCTION. 
During  the  summer  and  fall  of  1905  topographic  parties  under  Mr.  R.  II.  Chapman 
made  a  reconnaissance  topographic  map  of  an  area  in  southwestern  Nevada  and  eastern 
California.  The  writer  was  attached  to  the  parties  as  geologist,  under  the  general  super- 
vision of  Mr.  F.  L.  Ransome. 
The  topographic  map  is  on  a  scale  of  1 :253,440  (4  miles  to  the  inch),  with  contour  intervals 
of  100  feet,  and  covers  the  area  lying  between  36°  30'  and  38°  north  latitude  and  116° 
and  117°  30'  west  longitude.  This  area,  embracing  within  its  limits  8,550  square  miles,  is 
the  equivalent  of  nine  of  the  usual  30-minute  quadrangles  of  the  Geologic  Atlas  of  the 
United  States. 
The  territory  surveyed  was  so  great  that  in  many  cases  only  the  most  hasty  examination 
of  a  single  group  of  claims  in  a  district  was  possible,  and  naturally  an  attempt  was  made  to 
select  representative  groups.  But  little  mining  development  has  as  yet  been  done,  and 
extensive  underground  workings  were  nowhere  accessible.  With  few  exceptions,  the  rocks, 
fossils,  and  ores  have  not  been  examined  in  the  office  and  the  names  employed  are  wholly 
tentative.  The  assay  values  given  are  those  reported  by  the  prospectors,  and  in  most  cases 
represent  picked  samples.  A  forthcoming  bulletin  on  the  geology  of  the  area  will  be  accom- 
panied by  adequate  maps  outlining  the  areas  especially  favorable  for  prospecting. 
GEOGRAPHY. 
The  area  surveyed  lies  in  the  Great  Basin,  and  includes  portions  of  Esmeralda  and  Nye 
counties,  Nev.,  and  Inyo  County,  Cal.  The  mountain  ranges  of  the  eastern  portion  of  the 
area  have  a  north-south  trend,  while  the  Panamint  and  Grapevine  ranges  in  the  western 
portion  course  north-northwest,  more  nearly  parallel  to  the  crest  line  of  the  Sierra  Nevada. 
The  highest  peaks  reach  an  altitude  of  over  9,000  feet.  Between  the  mountains  are  broad 
inclosed  valleys,  covered  by  recent  sands  and  gravels.  Most  of  these  valleys  are  from  3,000 
to  5,000  feet  above  sea  level,  but  that  portion  of  Death  Valley  which  lies  within  the  area 
covered  by  the  map  sinks  to  280  feet  below  sea  level. 
Tonopah,  a  prosperous  mining  town  and  the  county  seat  of  Nye  County,  lies  4  miles 
north  of  the  area,  and  is  the  shipping  point  for  some  of  the  northern  and  northeastern 
camps  here  described.  The  central  portion  is  tributary  to  Goldfield,  where  there  are  val- 
uable gold  mines.  This  town  has  6,000  to  8,000  inhabitants,  and  is  the  present  railroad 
terminus.  The  southern  camps  hav«  the  sister  towns  of  Bullfrog,  Rhyolite,  and  Beatty 
as  supply  points. 
Goldfield  and  Tonopah  have  broad-gage  railroad  connections  with  the  Union  Pacific 
Railroad.  The  Carson  and  Colorado  Railroad  is  from  25  to  45  miles  west  of  the  area's 
western  border,  and  the  San  Pedro,  Salt  Lake  and  Los  Angeles  Railroad  lies  40  to  75  miles 
east  of  its  eastern  border.  A  railroad  has  been  surveyed  from  Goldfield  to  Bullfrog,  and  two 
roads  are  projected  from  the  San  Pedro,  Salt  Lake  and  Los  Angeles  Railroad  to  the  same 
point. 
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