66  CONTRIBUTIONS    TO    ECONOMIC    GEOLOGY,  1905. 
The  striking  similarity  between  the  ore  deposits  of  Silverbow  and  certain  of  those 
Goldfield  is  worthy  of  note.  Ascending  water,  carrying  silica  and  metallic  salts  in  soluti 
appears  to  have  deposited  its  burden  largely  in  preexisting  cavities.  Simultaneou 
waters  wandering  from  the  main  channels  silicified  contiguous  portions  of  the  rhyoli 
The  kaolinization  is  presumably  a  later  feature.  Movement  has  since  occurred  in  the  vei 
and  they  have  been  more  or  less  faulted  and  brecciated.  Surface  waters  have  altered  sib 
sulphides,  pyrite,  and  probably  less  amounts  of  chalcop}mte  to  the  corresponding  chlorid 
oxides,  and  carbonates,  while  secondary  sulphides  have  also  been  formed.  Gold,  probal 
originally  in  pyrite,  was  simultaneously  set  free. 
Timber  and  water  are  abundant  near  the  mines.  Goldfield  is  about  50  miles  distant 
road. 
Bldkes  Camp. — Blakes  Camp  is  located  on  one  of  a  number  of  rhyolite  inliers  whi 
protrude  from  the  "  wash  "  12  miles  northwest  of  Silverbow.  The  prospect  was  discover 
near  the  end  of  June,  1905.  A  fault  with  well-defined  walls  coursing  N.  80°  E.  cuts  t 
rhyolite.  Along  this  fault  a  zone  from  18  to  24  inches  wide  is  crushed  to  a  fine  clay 
which  arc  embedded  slickensided  fragments.  The  ground-up  rhyolite  is  white  or  stained  1 
hematite  or  limonite  and  to  a  less  extent  by  manganese  dioxide.  This  material  is  said 
pan  free  gold.     The  rhyolite  surrounding  the  fault  is  more  or  less  silicified. 
Eden. — The  mining  camp  of  Eden  is  situated  near  the  mouth  of  Little  Mill  Creek  Canyo 
on  the  cast  side  of  the  Kawich  Range.  The  first  locations  were  made  February  20,  1905, 1 
Mr.  John  Adams. 
Three  distinct  vertical  zones  of  mineralization  cross  Little  Mill  Creek  from  north-nort 
east  to  south-southwest,  respectively  one-fourth,  one-half,  and  five-eighths  mile  above  tl 
old  mill.  The  country  rock  is  rhyolite,  which  in  many  places  is  intensely  silicified  parallel 
the  mineralized  zones.  In  some  cases  the  only  indication  that  the  material  is  not  ve 
quartz  is  the  presence  of  phenocrysts  of  slightly  smoky  quartz.  Thin  sections  show  fir 
quartz  mosaics  replacing  both  groundmass  and  feldspar  phenocrysts.  While  the  conta 
between  the  silicified  and  the  unsilicified  rhyolite  is  as  a  rule  rather  sharp,  in  some  plac 
there  is  transition.  The  quartz  and  silicified  rhyolite  stand  out  in  distinct  walls,  apt! 
called  by  the  miners  "dikes,"  which  follow  the  mineralized  zones. 
The  central  zone  has  been  more  developed  than  the  others  and  was  studied  in  more  detai 
This  zone  is  situated  along  a  line  of  faulting  and  brecciation,  and  the  rhyolite  near  the  zor 
is  mashed.  The  mineralized  zone  varies  from  a  vein  of  quartz  3  feet  wide,  with  occasion; 
rhyolite  horses,  to  a  band  of  silicified  rhyolite  8  feet  wide,  intensely  netted  by  quartz  string 
ers.  Parallel  quartz  veins  more  or  less  continuous  and  connected  by  cross  veins  are  trans 
tional  between  the  two  forms  along  the  strike.  The  quartz,  often  crustified,  is  white  an 
more  or  less  iron  stained.  Finely  divided  sulphides  impart  a  blue  tinge  to  some  of  the  quart: 
and  the  parallel  position  in  thin  bands  of  the  white  and  blue  quartz  shows  clearly  thei 
contemporaneous  origin.  The  normal  crystalline  quartz  grades  into  a  compact,  whit( 
flinty  variety,  which  is  said  to  be  a  good  carrier  of  gold.  Vugs  usually  elongated  parallel  t 
the  walls  of  the  veins  are  characteristic.  Colorless  quartz  crystals  are  common  in  thes 
vugs,  while  botryoidal  quartz  walls  are  less  common.  The  vein  in  some  portions  is  com 
posed  of  clusters  of  quartz  plates  an  inch  in  length  set  at  right  angles  to  the  vein  walls 
This  central  zone  is  a  silver  bearer,  the  gold  values  being  one-tenth  those  of  silver.  A 
silver  ores,  ruby  and  native  silver  are  reported,  intimately  associated.  Secondary  silve 
chloride  in  knobs  and  wire-like  masses  is  widely  distributed  in  the  vugs,  and  the  silicifie 
rhyolite  itself  carries  values.     Iron  sulphide  was  noted  in  a  few  small  specks  in  vein  quarts 
The  upper  zone  of  mineralization  is  said  to  be  very  similar  to  the  middle  zone.  The  lowe 
zone  also  is  somewhat  similar  to  the  middle  zone,  although  there  is  perhaps  less  parallelisr 
and  constancy  of  the  quartz  veins.  The  strike  is  more  northerly.  Pyrite  locally  impreg 
nates  the  rhyolite.  The  flinty  quartz  already  mentioned  is  abundant  in  this  ledge,  and  th 
values  arc  largely  gold.  The  resemblance  of  the  Eden  deposits  to  those  at  Silverbow  i 
striking,  and  the  genesis  was  doubtless  similar. 
Water  and  fuel  are  abundant.     Tonopah,  the  supply  depot,  is  70  miles  distant. 
