﻿318 
  PROCEEDINGS 
  OF 
  THE 
  GEOLOGICAL 
  SOCIETY. 
  [Apr. 
  13, 
  

  

  and 
  on 
  the 
  south 
  by 
  the 
  northern 
  line 
  of 
  New 
  Mexico, 
  or 
  the 
  parallel 
  

   of 
  37°; 
  it 
  thus 
  extends 
  over 
  about 
  five 
  degrees 
  of 
  latitude 
  and 
  lon- 
  

   gitude, 
  and 
  contains 
  more 
  than 
  65,000 
  square 
  miles. 
  

  

  This 
  territory 
  comprises 
  a 
  large 
  part 
  of 
  the 
  great 
  basin 
  of 
  Fre- 
  

   mont, 
  the 
  general 
  physical 
  characters 
  of 
  which 
  have 
  been 
  so 
  often 
  

   described. 
  It 
  is 
  an 
  elevated 
  semi-desert 
  region, 
  its 
  surface 
  being 
  a 
  con- 
  

   stant 
  succession 
  of 
  longitudinal 
  mountain-ranges, 
  with 
  intermediate 
  

   valleys 
  and 
  plains, 
  most 
  of 
  which 
  are 
  independent 
  basins, 
  hemmed 
  

   in 
  by 
  mountains 
  on 
  all 
  sides 
  ; 
  and 
  the 
  whole 
  system 
  is 
  without 
  drain- 
  

   age 
  to 
  the 
  sea. 
  The 
  general 
  elevation 
  of 
  these 
  valleys 
  is 
  over 
  4500 
  

   feet 
  above 
  the 
  sea, 
  and 
  the 
  mountains 
  rise 
  from 
  1000 
  to 
  4000 
  feet, 
  

   and 
  in 
  some 
  instances, 
  perhaps, 
  to 
  8000 
  feet 
  higher. 
  

  

  The 
  Humboldt 
  is 
  the 
  principal 
  range 
  in 
  the 
  eastern 
  part 
  of 
  the 
  

   territory, 
  and 
  is 
  probably 
  even 
  more 
  lofty 
  than 
  the 
  Sierra 
  Nevada. 
  

   This 
  and 
  the 
  Goose 
  Creek 
  Range, 
  together 
  with 
  most 
  of 
  the 
  others, 
  

   run 
  in 
  a 
  north 
  and 
  south 
  direction, 
  and 
  have 
  rugged 
  and 
  precipitous 
  

   slopes. 
  The 
  Washoe 
  or 
  Silver 
  Eange, 
  upon 
  the 
  flanks 
  of 
  which 
  the 
  

   principal 
  gold- 
  and 
  silver-veins 
  have 
  been 
  discovered, 
  extends 
  for 
  

   nearly 
  fifteen 
  miles 
  parallel 
  with 
  the 
  Sierra 
  Nevada, 
  and 
  about 
  

   twenty 
  miles 
  east 
  of 
  it. 
  The 
  included 
  valley 
  is 
  partly 
  occupied 
  by 
  

   Washoe 
  Lake, 
  and 
  is 
  known 
  as 
  Washoe 
  Valley. 
  

  

  II. 
  Geology. 
  — 
  Very 
  little 
  is 
  yet 
  known 
  of 
  the 
  geology 
  of 
  the 
  

   Nevada 
  Territory, 
  and 
  it 
  presents 
  a 
  most 
  interesting 
  and 
  promising- 
  

   field 
  for 
  future 
  exploration. 
  We 
  may 
  say, 
  generally, 
  that 
  it 
  is 
  a 
  

   region 
  of 
  intense 
  igneous 
  disturbance 
  and 
  metamorphism, 
  and 
  that 
  

   the 
  prevailing 
  rocks 
  are 
  granitic, 
  metamorphic, 
  and 
  porphyritic, 
  with 
  

   trap, 
  basalt, 
  and 
  lava, 
  the 
  porphyries 
  and 
  igneous 
  rocks 
  being 
  very 
  

   common. 
  Carboniferous 
  limestones 
  and 
  sandstones 
  have 
  been 
  ob- 
  

   served 
  in 
  the 
  Humboldt 
  Mountains, 
  and 
  in 
  the 
  ranges 
  eastward 
  to 
  

   the 
  Great 
  Salt 
  Lake. 
  The 
  extent 
  of 
  this 
  formation 
  is 
  not 
  known. 
  

  

  In 
  the 
  absence 
  of 
  further 
  general 
  information 
  upon 
  the 
  geology 
  

   of 
  Nevada, 
  the 
  following 
  notes 
  made 
  upon 
  the 
  route 
  from 
  California 
  

   to 
  the 
  principal 
  mines 
  are 
  presented 
  to 
  the 
  Society 
  7 
  . 
  On 
  entering 
  

   the 
  Territory 
  from 
  California 
  by 
  the 
  route 
  up 
  the 
  south 
  fork 
  of 
  the 
  

   American 
  River 
  from 
  Racerville, 
  we 
  find 
  a 
  compact 
  homogeneous 
  

   granite 
  of 
  a 
  grey 
  colour, 
  extending 
  on 
  both 
  sides 
  of 
  Truckee 
  or 
  

   Bigler 
  Lake, 
  and 
  forming 
  the 
  main 
  bulk 
  of 
  the 
  double 
  crest 
  of 
  the 
  

   Sierra 
  Nevada. 
  One 
  of 
  these 
  crests 
  is 
  within 
  the 
  limits 
  of 
  Nevada, 
  

   and 
  stretches 
  far 
  to 
  the 
  north 
  and 
  south 
  in 
  a 
  line 
  of 
  summits, 
  which 
  

   are 
  covered 
  with 
  snow 
  for 
  the 
  greater 
  part 
  of 
  the 
  year. 
  From 
  the 
  

   summit 
  of 
  Daggett's 
  Pass, 
  an 
  elevation 
  of 
  more 
  than 
  6000 
  feet, 
  

   there 
  is 
  a 
  fine 
  view 
  of 
  the 
  valley 
  of 
  Carson 
  River, 
  which 
  is 
  about 
  

   2000 
  feet 
  below. 
  The 
  descent 
  is 
  rapid, 
  and 
  by 
  a 
  fine 
  road, 
  or 
  grade, 
  

   cut 
  zigzag 
  in 
  the 
  half-decomposed 
  granite 
  of 
  the 
  steep 
  slope. 
  On 
  

   reaching 
  the 
  valley, 
  the 
  road 
  is 
  over 
  the 
  drift-accumulation 
  from 
  

   the 
  mountains, 
  and 
  along 
  the 
  borders 
  of 
  the 
  later 
  alluvial 
  deposits 
  of 
  

   Carson 
  River, 
  until 
  the 
  town 
  of 
  Genoa 
  is 
  reached, 
  where 
  the 
  rocks 
  

   change 
  and 
  the 
  surface 
  is 
  covered 
  by 
  boulders 
  and 
  fragments 
  of 
  

   metamorphosed 
  rocks 
  (of 
  sandstone 
  and 
  clay-slate), 
  which 
  skirt 
  the 
  

   base 
  of 
  the 
  granite-mountains. 
  In 
  a 
  line 
  with 
  them, 
  further 
  north 
  

  

  