spurk]        ORE    DEPOSITS   OF  SILVER    PEAK    QUADRANGLE,    NEV.        117 
has  been  done,  but  with  unsatisfactory  results.  It  seems  to  he  the 
general  outcome  of  all  investigations  that,  except  locally,  the  sand  of 
these  dunes  does  not  contain  more  than  a  trace  of  gold.  The  sample 
taken  by  the  writer  assayed  a  trace  of  gold  and  silver. 
SUMMARY. 
To  sum  up  the  ore  deposits  of  the  Silver  Peak  quadrangle  it  may  be 
repeated  that  they  are  all  connected  with  intrusive  granitic  rock  and 
lie  either  within  this  granite  or  (more  often)  in  the  Paleozoic  limestone 
into  which  this  is  intrusive.  The  age  of  all  the  deposits  is  pre- 
Tertiary.  The  ores  have  been  formed  in  part  directly  as  ultra- 
siliceous  segregations  from  the  granite;  in  part  by  the  action  of 
solutions  from  the  granite  on  the  adjacent  limestones.  The  most 
important  district,  the  gold  district  of  Silver  Peak,  belongs  in  the 
first  class,  and  the  others  mainly  in  the  second  class.  These  others, 
except  the  Windypah  district,  as  before  stated,  were  prospected  and 
abandoned  years  ago,  and  owe  their  recent  activity  directly  to  interest 
produced  by  the  discovery  of  Tonopah.  Many  of  the  veins  in  them 
are  not  highly  encouraging.  However,  some  of  the  mines  in  the  Lone 
Mountain  district  have  recentty  produced  considerable  shipping  ore; 
for  example,  the  Alpine  has  shipped  over  $70,000  worth  within  the  last 
year.  Some  of  the  prospects  within  the  Windypah  district  appear 
worthy  of  investigation.  The  Silver  Peak  district  proper  is  a  vast 
treasury  of  low-grade  gold  ores. 
