﻿324 
  PROCEEDINGS 
  OF 
  THE 
  GEOLOGICAL 
  SOCIETY. 
  [Apr. 
  13> 
  

  

  These 
  springs 
  are 
  nearly 
  in 
  the 
  line 
  of 
  prolongation 
  of 
  the 
  hot 
  

   springs 
  at 
  the 
  base 
  of 
  the 
  Sierra, 
  near 
  Genoa, 
  and 
  those 
  at 
  Carson 
  

   City, 
  already 
  noticed 
  ; 
  and 
  they 
  indicate 
  an 
  extensive 
  fissure, 
  or 
  line 
  

   of 
  disruption, 
  extending 
  north 
  and 
  south 
  and 
  parallel 
  with 
  that 
  

   chain. 
  

  

  Other 
  hot 
  springs 
  are 
  found 
  along 
  the 
  Humboldt 
  Mountains, 
  and 
  

   in 
  the 
  valley 
  of 
  Walker's 
  River, 
  near 
  the 
  Emigrant-trail. 
  At 
  the 
  

   head 
  of 
  Honey 
  Lake 
  there 
  are 
  springs 
  remarkable 
  for 
  their 
  volume, 
  

   and 
  for 
  the 
  constant 
  boiling 
  of 
  the 
  water. 
  This 
  locality, 
  although 
  

   said 
  to 
  be 
  within 
  the 
  limits 
  of 
  California, 
  is 
  in 
  the 
  Great 
  Basin, 
  and 
  

   has 
  all 
  its 
  surrounding 
  physical 
  features 
  in 
  common 
  with 
  those 
  of 
  

   Nevada. 
  The 
  occurrence 
  of 
  a 
  bed 
  of 
  basaltic 
  lava 
  capping 
  the 
  slight 
  

   knoll 
  near 
  the 
  Steamboat 
  Springs 
  is 
  interesting, 
  and 
  may 
  have 
  some 
  

   connexion 
  with 
  their 
  origin. 
  The 
  extent 
  and 
  source 
  of 
  this 
  lava 
  

   were 
  not 
  ascertained. 
  

  

  Extinct 
  craters 
  and 
  beds 
  of 
  lava 
  are 
  reported 
  to 
  exist 
  in 
  various 
  

   parts 
  of 
  the 
  Territory 
  ; 
  but 
  no 
  high 
  volcanic 
  cones, 
  extinct 
  or 
  active, 
  

   have 
  yet 
  been 
  ascertained 
  to 
  exist*. 
  

  

  In 
  conclusion, 
  I 
  may 
  say 
  that 
  the 
  facts 
  presented, 
  together 
  with 
  

   those 
  about 
  to 
  be 
  given 
  upon 
  the 
  mineral 
  veins, 
  although 
  scanty, 
  

   corroborate 
  the 
  statement 
  that 
  the 
  lithology 
  and 
  mineralogy 
  of 
  this 
  

   Territory 
  are 
  very 
  similar 
  to 
  those 
  of 
  the 
  table-land 
  of 
  Arizona, 
  

   Sonora, 
  and 
  Mexico. 
  

  

  IV. 
  Principal 
  Mines 
  and 
  Veins. 
  — 
  The 
  presence 
  of 
  gold 
  in 
  places 
  

   on 
  the 
  eastern 
  side 
  of 
  the 
  Sierra 
  Nevada, 
  about 
  Carson 
  Yaliey 
  and 
  

   Genoa, 
  was 
  well 
  known 
  before 
  1858. 
  

  

  The 
  Virginia 
  mining-district 
  is 
  established 
  upon 
  the 
  Cornstock 
  

   vein, 
  and 
  includes 
  all 
  the 
  mines 
  on 
  the 
  eastern 
  slope 
  of 
  Mount 
  

   Davidson 
  and 
  those 
  on 
  Mount 
  Cedar, 
  an 
  adjoining 
  elevation 
  to 
  the 
  

   north. 
  The 
  Cornstock 
  vein 
  is 
  subdivided 
  into 
  sixteen 
  claims, 
  the 
  

   principal 
  of 
  which 
  will 
  now 
  be 
  examined 
  in 
  detail. 
  

  

  1. 
  Ophir 
  Mine. 
  — 
  The 
  general 
  characters 
  of 
  the 
  Cornstock 
  lode 
  are 
  

   shown 
  to 
  better 
  advantage 
  in 
  this 
  claim 
  than 
  in 
  either 
  of 
  the 
  others, 
  

   owing 
  to 
  the 
  greater 
  amount 
  of 
  mining 
  upon 
  it. 
  It 
  is 
  here 
  seen 
  to 
  

   cut 
  through 
  the 
  porphyry 
  of 
  Mount 
  Davidson 
  in 
  a 
  nearly 
  north 
  and 
  

   south 
  direction, 
  with 
  a 
  westerly 
  dip 
  of 
  about 
  70°. 
  It 
  rises 
  to 
  the 
  

   surface 
  within 
  the 
  limits 
  of 
  Virginia 
  City. 
  There 
  was 
  no 
  outcrop 
  

   visible, 
  or 
  but 
  a 
  slight 
  one 
  at 
  intervals, 
  the 
  gangue 
  or 
  vein-stone 
  

   being 
  so 
  soft 
  and 
  friable 
  that 
  it 
  was 
  completely 
  broken 
  down 
  and 
  

   mingled 
  with 
  the 
  soil. 
  The 
  bold 
  outcrop 
  of 
  the 
  Virginia 
  ledge 
  is, 
  

   however, 
  directly 
  above 
  it, 
  and 
  is 
  like 
  a 
  dyke 
  curving 
  over 
  the 
  

   summits 
  of 
  the 
  spurs 
  from 
  the 
  mountains. 
  The 
  Ophir 
  Mine 
  is 
  

   worked 
  to 
  a 
  depth 
  of 
  200 
  feet 
  : 
  the 
  general 
  structure 
  of 
  the 
  vein 
  is 
  

   shown 
  by 
  the 
  accompanying 
  section 
  from 
  wall 
  to 
  wall. 
  

  

  * 
  J. 
  C. 
  Fremont 
  traversed 
  considerable 
  portions 
  of 
  this 
  Territory 
  in 
  his 
  

   explorations 
  across 
  the 
  continent, 
  and 
  observations 
  on 
  the 
  rock-formations 
  he 
  

   saw 
  may 
  be 
  found 
  in 
  his 
  Eeport. 
  Some 
  will 
  also 
  be 
  found 
  in 
  the 
  Eeport 
  of 
  

   Lieut. 
  Bickwith 
  and 
  Dr. 
  Schiel, 
  in 
  the 
  volume 
  of 
  the 
  U. 
  S. 
  Pacific 
  R. 
  JR. 
  

   Evpl. 
  and 
  Surveys. 
  I 
  have 
  not 
  been 
  able 
  to 
  obtain 
  access 
  to 
  either 
  of 
  these 
  

   works. 
  

  

  