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being  siliceous  phases  of  a  granitic  magma.  The  gold  in  the  quartz 
is  usually  free,  sometimes  associated  with  scattered  galena.  Green- 
stone or  diorite  dikes  cut  the  veins  or  follow  along  them,  but  are  of 
later  age.  Along  the  dikes  there  has  been  water  circulation,  resulting 
sometimes  in  impoverishment,  sometimes  in  relative  concentration,  of 
the  original  values. 
This  zone  of  veins  outcrops  for  a  mile  along  the  mountain  side.  At 
one  point,  some  distance  below  the  vein  zone,  free  gold  in  fresh  alaskite- 
pegmatite  countiy  rock  was  found. 
In  the  main  the  other  gold  mines  or  prospects  of  the  district  have 
exactly  the  same  geological  relations. 
LONE   MOUNTAIN   DISTRICT. 
The  ore  deposits  of  this  region  are  situated  within  a  moderate  dis- 
tance of  two  masses  of  intrusive  granitic  rock,  one  of  which  makes 
up  Lone  Mountain  Peak  proper,  while  the  other  lies  in  the  lower 
mountains  to  the  south.  The  properties  visited  by  the  writer  include 
the  Paymaster,  Esperanza,  Utopia,  and  Alpine,  the  Weepah  district, 
and  numerous  other  mines  and  prospects.  The  first  three  mentioned 
all  belong  in  the  same  class,  being  small,  nonpersistent  quartz  veins 
in  Cambrian  limestone  and  slate.  These  veins  are  generally,  but  not 
always,  parallel  with  the  stratification.  They  follow  crushed  zones  or 
selvages  formed  by  movement  in  the  limestones,  possibly  attendant 
upon  faulting.  The  ore  in  the  veins  consists  of  small  amounts  of  rich 
silver-copper  sulphides,  with  some  galena,  pyrite,  and  secondary 
minerals  such  as  chrysocolla,  limonite,  and  probably  chloro-bromides 
of  silver. 
The  Alpine  mine  is  situated  near  the  contact  of  the  Lone  Mountain 
granite  with  a  series  of  metamorphic  marbles  and  some  interbedded 
schists.  In  the  marbles  are  seams  of  ore  parallel  with  the  stratifica- 
tion. Small  quartz  seams  containing  galena  are  low-grade  silver  ores. 
These  lead  into  bodies  of  mixed  galena  and  argentiferous  lead  car- 
bonate, which  widen  out  into  irregular  pockets  and  constitute  the  ore 
that  is  mined.  The  ore  bodies  follow  a  certain  horizon  around  a  hill, 
with  lesser  seams  above  and  below.  Diorite  sheets  and  crosscutting 
dikes  are  frequent  but  are  not  in  any  way  associated  with  the  ore. 
The  area  of  intrusive  granite  above  noted  as  lying  south  of  the  Lonei 
Mountain  granite  is  marked  Ivy  considerable  contact  metamorphism  in 
the  limestone  and  shale  into  which  it  is  intrusive.  On  its  eastern  side 
this  contact  metamorphism  has  been  accompanied  by  some  mineral 
deposition.  There  was  here  noted,  interstratified  with  schistose  slates 
and  crystalline  limestones,  a  metamorphosed  belt  about  60  feet  wide 
and  traceable  for  a  long  distance.  This  zone  is  characterized  by 
epidote,  garnet,  chalcopyrite,  calcite,  magnetite,  specular  iron,  pyrite, 
and  galena,  with  certain  secondary  minerals— chrysocolla,  limonite, 
