SOUTHWESTERN    NEVADA    AND    EASTERN    CALIFORNIA.  01 
a  heavily  iron-stained  chalcedony  was  deposited  in  intimate  association  with  the  -oxidized 
ores.  Later,  in  some  instances,  drusy  quartz  was  deposited  upon  the  copper  carbonates. 
The  development  is  altogether  too  slight  to  determine  what  part  of  the  secondary  copper 
ores  has  been  concentrated  from  sulphides  originally  lying  in  limestone  now  removed  by 
erosion.  It  is  probable,  however,  that  a  considerable  proportion  is  of  such  origin  and  that 
when  the  oxidized  ores  are  worked  out  the  copper  content  will  decrease.  It  may  well  be, 
however,  that  in  this  portion  of  the  desert  region  the  water  level  is  very  deep. 
In  the  rhyolite  north  of  the  east  end  of  the  copper  belt  are  some  prospects.  The  values 
reported  from  these  are  gold  and  these  deposits  are  undoubtedly  to  be  more  nearly  correlated 
with  the  Tertiary  mineralization  of  the  Bullfrog  and  certain  of  the  Goldfield  ore  deposits. 
Water  for  the  district  at  present  is  hauled  from  the  Stonewall  Springs,  17  miles  distant. 
Available  wood,  except  the  almost  valueless  yucca,  is  equally  distant.  However,  the 
Cuprite  mines  are  only  18  to  25  miles  from  the  railroad  at  Goldfield,  and  ore  may  be  shipped 
from  the  district  at  a  comparatively  low  cost. 
Lida. — Lida  is  situated  on  the  western  border  of  the  area  surveyed,  about  34  miles  south 
of  its  northwest  corner.  A  daily  stage  runs  from  Lida  to  the  railroad  at  Goldfield.  The 
Lida  mining  district  was  organized  August  28,  1871,  and  in  the  succeeding  decade  some 
rich  surface  pockets  of  horn  silver  and  silver-bearing  galena  were  removed.  The  ore, 
probably  picked,  ran  from  $500  to  $1,000  per  ton.  In  the  latter  part  of  1904  and  the  early 
part  of  1905,  the  attention  of  mining  men  having  been  turned  to  southwestern  Nevada, 
old  mines  were  reopened  and  new  locations  made.  Unfortunately,  at  the  time  of  the 
writer's  visit  in  December,  1905,  the  principal  prospects  were  closed  through  litigation 
and  in  many  cases  pumps  and  ladders  had  been  removed. 
The  country  rock  in  the  vicinity  of  Lida  consists  of  dark-gray  limestones  and  olive- 
green  shales  of  Cambrian  age.  These  sediments  are  in  the  main  gently  folded,  although 
locally  considerably  disturbed.  Small  faults  also  occur.  The  limestone  and  shales  are 
widely  and  in  many  places  most  intensely  injected  by  a  granite-porphyry  which  may  per- 
haps be  correlated  with  the  post-Jurassic  granite  intrusions.  Dikes  of  diorite-porphyry 
also  cut  the  sedimentary  rocks.  So  far  as  a  hasty  examination  showed,  these  masses  of 
igneous  rock  are  not  closely  connected  structurally  with  the  ore  deposits.  The  prospects 
are  situated  partly  outside  the  area  surveyed  and  partly  on  Mount  Macgruder,  to  the  south 
and  southeast  of  the  village.  The  latter  prospects  alone  were  examined  and  in  most  cases 
only  the  dumps  were  accessible. 
The  Florida-Goldfield  Mining  Company's  shaft  is  situated  near  the  mouth  of  a  gulch 
which  joins  the  Lida  Valley  about  one-half  mile  below  the  village.  When  visited,  the 
shaft,  150  feet  deep,  was  filled  with  water  to  within  80  feet  of  the  surface.  The  ore  on  the 
dump  included  Cambrian  limestone  rather  heavily  impregnated  with  iron  pyrites,  pyrite 
inclosed  in  veins  of  coarsely  crystalline  white  calcite,  and  the  same  ore  in  white  quartz 
veinlets.  In  some  specimens  galena  and  light-brown  zinc  blende  were  associated  with 
the  quartz  veinlets  carrying  pyrite.  Another  and  apparently  still  more  uncommon  sul- 
phide, chalcopyrite,  is  sometimes  superficially  altered  to  malachite  and  azurite.  The  lime- 
stone cut  by  the  quartz  veins  has  been  more  or  less  silicified.  An  old  open  cut  above  this 
shaft  shows  a  zone  of  brecciated  limestone  4  feet  in  width  healed  by  innumerable  connect- 
ing quartz  veinlets  in  which  the  above  ores  occur. 
On  the  dump  of  the  Thanksgiving  mine  quartz  masses  and  veinlets  cutting  similar  lime- 
stone were  examined.     In  the  quartz  is  much  pyrite  and  less  chalcopyrite. 
The  Lida  deposits  are  partially  fissure  fillings  and  partially  impregnations  of  the  count  ry 
rock.  The  oxidized  ores  appear  to  be  largely  replacements  of  the  limestone.  The  oxidized 
zone  is,  for  a  desert  country,  very  shallow. 
In  the  early  days  of  mining  in  the  district  considerable  bunches  of  oxidized  ore  were 
hauled  to  Austin  and  Belmont.  It  is  scarcely  probable  that  all  of  these  pockets  have  been 
found,  and,  with  the  improved  transportation  facilities,  such  deposits  should  pay  well. 
Some  of  the  ore  mined  from  the  newly  located  prospects  is  reported  to  run  from  $100  to 
