﻿INTRODUCTION. 
  11 
  

  

  in 
  the 
  early 
  fifties. 
  a 
  In 
  the 
  report 
  on 
  this 
  work 
  the 
  larger 
  topo- 
  

   graphic 
  features 
  were 
  well 
  described, 
  the 
  presence 
  of 
  asphaltic 
  rocks 
  

   was 
  briefly 
  noted, 
  and 
  the 
  Tertiary 
  age 
  of 
  most 
  of 
  the 
  sedimentary 
  

   rocks 
  was 
  recognized, 
  but 
  the 
  structural 
  features 
  and 
  the 
  relations 
  of 
  

   the 
  rocks 
  were 
  in 
  the 
  main 
  misinterpreted. 
  

  

  During 
  the 
  course 
  of 
  the 
  geological 
  survey 
  of 
  California 
  by 
  J. 
  D. 
  

   Whitney 
  a 
  hasty 
  reconnaissance 
  was 
  made 
  of 
  a 
  part 
  of 
  this 
  region. 
  6 
  

   He 
  says 
  in 
  his 
  report 
  : 
  

  

  The 
  region 
  to 
  the 
  west 
  of 
  the 
  San 
  Rafael 
  Range, 
  between 
  the 
  Santa 
  Ynez 
  and 
  Cuya- 
  

   mas 
  rivers, 
  was^ 
  cursorily 
  examined 
  by 
  our 
  party. 
  * 
  * 
  * 
  The 
  region 
  is 
  occupied 
  

   by 
  hills 
  of 
  moderate 
  height. 
  No 
  metamorphic 
  rock 
  was 
  seen; 
  but 
  pebbles 
  of 
  serpen- 
  

   tine 
  and 
  metamorphic 
  sandstone 
  were 
  noticed, 
  especially 
  for 
  3 
  or 
  4 
  miles 
  north 
  

   of 
  Alamo 
  Pintado. 
  * 
  * 
  * 
  These 
  hills 
  were 
  covered 
  with 
  gravel 
  derived 
  from 
  the 
  

   bituminous 
  slates. 
  At 
  times, 
  especially 
  near 
  the 
  Santa 
  Maria 
  River, 
  the 
  hills 
  were 
  

   capped 
  by 
  a 
  modern 
  horizontal 
  deposit 
  (post-Pliocene?). 
  The 
  underlying 
  rock, 
  

   when 
  seen, 
  was 
  the 
  bituminous 
  slate, 
  sometimes 
  dipping 
  to 
  the 
  north 
  and 
  sometimes 
  

   to 
  the 
  south. 
  

  

  Near 
  Foxen's, 
  on 
  the 
  south 
  side 
  of 
  the 
  valley, 
  there 
  were 
  hills 
  of 
  nearly 
  horizontal 
  

   strata 
  from 
  200 
  to 
  300 
  feet 
  high, 
  the 
  north 
  slopes 
  of 
  which 
  were 
  very 
  steep, 
  usually 
  

   about 
  35°. 
  Beneath 
  the 
  soft 
  sandstone, 
  which 
  made 
  up 
  the 
  principal 
  part 
  of 
  these 
  

   hills, 
  was 
  a 
  stratum 
  of 
  infusorial 
  rock 
  resembling 
  chalk 
  in 
  appearance, 
  exceedingly 
  

   light, 
  its 
  specific 
  gravity 
  not 
  being 
  more 
  than 
  0.6 
  or 
  0.7; 
  the 
  thickness 
  of 
  this 
  stratum, 
  

   was 
  over 
  20 
  feet. 
  The 
  age 
  of 
  this 
  formation 
  is 
  not 
  yet 
  definitely 
  ascertained. 
  

  

  North 
  of 
  the 
  valley, 
  at 
  Foxen's, 
  the 
  bituminous 
  slate 
  occurs 
  with 
  a 
  high 
  dip 
  to 
  the 
  

   north, 
  and 
  asphaltum 
  is 
  found 
  in 
  several 
  localities 
  near. 
  In 
  places 
  the 
  slates 
  are 
  

   altered 
  and 
  silicified, 
  sometimes 
  resembling 
  semiopal 
  in 
  appearance, 
  the 
  finest 
  lami- 
  

   nae 
  of 
  the 
  original 
  structure 
  being 
  preserved. 
  

  

  So 
  far 
  as 
  the 
  writers 
  are 
  aware 
  no 
  further 
  investigation 
  of 
  the 
  geol- 
  

   ogy 
  of 
  the 
  region 
  was 
  made 
  until 
  H. 
  W. 
  Fairbanks 
  made 
  examina- 
  

   tions 
  of 
  portions 
  of 
  the 
  Coast 
  Ranges 
  and 
  reported 
  on 
  them 
  for 
  the 
  

   State 
  mining 
  bureau 
  in 
  1894. 
  In 
  his 
  paper 
  on 
  the 
  " 
  Geology 
  of 
  

   northern 
  Ventura, 
  Santa 
  Barbara, 
  San 
  Luis 
  Obispo, 
  Monterey, 
  and 
  

   San 
  Benito 
  counties" 
  reference 
  is 
  made 
  c 
  to 
  the 
  region 
  under 
  discus- 
  

   sion, 
  especially 
  to 
  the 
  Santa 
  Ynez 
  Mountains. 
  Regarding 
  the 
  Santa 
  

   Ynez 
  Range 
  he 
  says: 
  "It 
  is 
  formed, 
  so 
  far 
  as 
  is 
  known, 
  of 
  Miocene 
  

   rocks 
  exclusively." 
  And 
  again: 
  

  

  There 
  can 
  be 
  no 
  doubt 
  that 
  the 
  main 
  portion 
  of 
  the 
  Santa 
  Ynez 
  Range 
  is 
  Miocene 
  

   with 
  a 
  general 
  anticlinal 
  structure, 
  well 
  shown 
  in 
  the 
  San 
  Marcos 
  Pass. 
  The 
  center 
  

   of 
  the 
  anticlinal 
  is 
  not 
  generally 
  the 
  highest 
  portion 
  of 
  the 
  range, 
  but 
  lies 
  on 
  the 
  east- 
  

   ern 
  slope. 
  The 
  normal 
  type 
  of 
  anticlinal 
  structure 
  is 
  also 
  marked 
  by 
  an 
  east 
  and 
  west 
  

   compression, 
  producing 
  features, 
  however, 
  of 
  secondary 
  importance. 
  

  

  As 
  viewed 
  from 
  the 
  south 
  at 
  various 
  points 
  the 
  range 
  consists 
  of 
  heavy-bedded 
  sand- 
  

   stone, 
  dipping 
  at 
  a 
  high 
  angle 
  to 
  the 
  south. 
  * 
  * 
  * 
  At 
  the 
  western 
  end, 
  in 
  the 
  vicin- 
  

   ity 
  of 
  Point 
  Arguello, 
  no 
  anticlinal 
  structure 
  is 
  apparent, 
  but 
  steeply 
  inclined 
  and 
  

   broken 
  strata. 
  Asphaltum 
  is 
  found 
  in 
  many 
  places 
  near 
  the 
  sea 
  from 
  Point 
  Arguello 
  

   to 
  Ventura 
  County. 
  

  

  a 
  Pacific 
  R. 
  R. 
  Repts., 
  vol. 
  7, 
  1857, 
  Chaps. 
  VIII, 
  IX, 
  and 
  X. 
  

  

  & 
  Geological 
  Survey 
  of 
  California, 
  Geology, 
  vol. 
  1, 
  1865, 
  pp. 
  135-138. 
  

  

  c 
  Twelfth 
  Ann. 
  Rept. 
  California 
  State 
  Mining 
  Bureau, 
  1894, 
  pp. 
  498-506. 
  

  

  