SOUTHWESTERN    NEVADA    AND    EASTERN    CALIFORNIA.  71 
in  width  from  2  inches  to  1  foot  and  can  be  traced  several  hundred  feet.  Four  feet  awn y  is 
a  parallel  vein,  the  two  being  connected  by  a  few  chrysocolla  stringers.  The  vein  is  com- 
posed of  a  mottled  mosaic  of  chrysocolla  and  a  dark,  compact,  jaspery  quartz,  stained  in  some 
cases  by  limonite  and  in  others  by  manganese  dioxide.  The  chrysocolla  is  usually  verdigris 
green,  although  picked  pieces  are  a  beautiful  robin's  egg  blue.  The  substance  is  usually 
opaque,  but  some  is  slightly  translucent.  The  chrysocolla  is  commonly  massive,  sometimes 
with  a  botryoidal  structure,  and  in  some  massive  phases  an  occasional  cleavage  face  is  seen. 
The  chrysocolla  is  cut  by  managanese  dioxide  and  white  calcite  or  quartz  veinlets. 
Chrysocolla  veinlets  of  slightly  different  color  cut  one  another,  showing  that  the  formation 
of  this  mineral  extended  over  a  considerable  period.  Associated  with  it  is  a  crystalline, 
bottle-green,  semitransparent  mineral  whose  cleavage  faces  reach  a  length  of  one-half  inch. 
A  radial  structure  is  sometimes  observed.  This  mineral  is  embedded  in  the  chrysocolla 
or  cuts  it  in  veins  and  is  of  contemporaneous  age.  It  is  probably  brochantite,  a  hydrous 
sulphate  of  copper.  Both  the  chrysocolla  and  brochantite,  were  determined  by  Dr.  Wal- 
demar  T.  Schaller.     Post-mineral  faults  cut  the  veins  and  parallel  them. 
In  these  copper  deposits  the  minerals  exposed  are  all  secondary.  Malachite,  chrysocolla, 
brochantite,  cerussite,  a  jaspery  quartz,  and  limonite  seem  practically  contemporaneous. 
There  is  considerable  evidence  that  the  formation  of  the  copper  minerals  and  the  jaspery 
quartz  extended  over  a  considerable  period,  during  which  some  fracturing  occurred,  and  in 
consequence  the  relations  between  these  minerals  are  complex.  They  partly  replace  the 
limestone  and  partly  fill  fissures.     Azurite,  quartz,  and  calcite  are  of  later  origin. 
The  pieces  of  robin's  egg  blue  chrysocolla  closely  resemble  turquoise,  and  several  hundred 
pounds  of  the  mineral  have  been  sold  for  this  gem.  The  mineral  takes  an  excellent  polish. 
The  largest  piece  of  pure  chrysocolla  seen  was  6  by  3  by  2  inches. 
Oak  Spring  furnishes  good  water  sufficient  for  domestic  purposes  and  several  other 
springs  exist  in  the  general  vicinity.  The  Oak  Spring  butte  is  timbered  to  some  extent. 
Caliente,  on  the  San  Pedro,  Salt  Lake  and  Los  Angeles  Railroad  is  the  natural  shipping  point. 
Bare  Mountain. — Bare  Mountain  forms  the  east  wall  of  the  Amargosa  desert,  from  Gold 
Center  to  a  point  20  miles  south.  The  rugged  mountain  ridge  is  intensely  dissected  by 
V-shaped  canyons.  The  surrounding  hills  are  composed  of  Tertiary  rhyolitic  and  basaltic 
rocks,  but  the  mountains  themselves  are  formed  of  sedimentary  rocks.  Limestone  is  the  pre- 
dominant rock,  probably  of  Ordovician  age  for  the  most  part.  The  limestone  is  mostly  black 
in  color  and  of  fine  grain,  although  areas,  particularly  in  the  northern  part,  are  white  marble 
of  medium  grain.  Interbedded  with  the  limestones  are  light-colored  quartzites  and  silvery 
muscovite-schists.  At  the  north  end  of  the  range  pegmatite  dikes  are  rather  common.  A 
few  intrusions  of  a  dioritic  rock  are  also  found  here.  The  limestone  has  been  complexly 
folded  and  vertical  dips  are  common.  Faults  frequently  occur,  reversed  faults  perhaps 
being  more  common  than  normal  faults. 
Quartz  veins  are  common  in  the  north  end  of  the  range  and  mineral  locations  were  made 
on  some  of  them  early  in  1905.  An  older  set  of  veins,  sometimes  folded,  is  faulted  by  a 
younger  set. 
The  Decillion  claim  is  located  in  the  northwestern  portion  of  the  range  near  the  mouth  of 
a  deep  canyon.  The  principal  development  work  is  a  50-foot  shaft.  Quartz  veins  and 
stringers  reaching  a  maximum  thickness  of  1  foot  cut  limestone  and  schist.  Some  of  the 
veins  strike  east  and  west  and  dip  45°  S.  Chalcopyrite  in  grains  up  to  one-half  inch  in  diam- 
eter is  disseminated  through  the  quartz.  Malachite  and  a  little  azurite  stain  the  quartz 
around  the  sulphide  and  have  been  deposited  in  cavities  in  the  quartz.  The  quartz  vein 
since  its  deposition  has  been  faulted  and  crushed,  the  crushed  fragments  being  in  places 
cemented  by  granular  gypsum,  while  gypsum  crystals  line  some  cavities.  The  ore  of  this 
mine  is  said  to  run  high  in  silver,  with  low  gold  values. 
The  two  50-foot  shafts  of  the  Kismet  Mining  Company,  better  known  as  I  he  Lonsway 
property,  are  situated  on  the  crest  of  a  high  ridge  \\  miles  southwest  of  Beatty.  The  coun- 
try rock  here,  a  quartzite,  strikes  N.  35°  W.  and  dips  15°  NE.  The  quartz  vein,  which  is 
traceable  several  hundred  feet,  is  from  1^  to  2  feet  wide.     It  strikes  N.  85°  W.  and  dips  55°  S. 
