﻿78 
  SANTA 
  MABIA 
  OIL 
  DISTRICT, 
  CALIFORNIA. 
  

  

  Faults 
  also 
  occur 
  along 
  the 
  Franciscan-Fernando 
  contact 
  in 
  the 
  

   region 
  northwest 
  and 
  southeast 
  of 
  Figueroa 
  Creek, 
  bul 
  the 
  resultant 
  

   throw 
  was 
  not 
  determined. 
  A 
  deposit 
  tonal 
  contact 
  is 
  clearly 
  exposed 
  

   along 
  this 
  same 
  line 
  just 
  northwest 
  of 
  Alamo 
  Pintado 
  Creek. 
  

  

  i;\ 
  [DENCKs 
  «)F 
  l'KTKOLEUM. 
  

  

  Despite 
  the 
  great 
  development 
  of 
  folds 
  within 
  the 
  Monterey 
  area, 
  

   only 
  here 
  and 
  there 
  do 
  seepages 
  of 
  asphaltic 
  material 
  occur. 
  It 
  

   would 
  seem 
  that 
  the 
  fractures 
  produced 
  by 
  sharp 
  folding 
  would 
  give 
  

   adequate 
  channels 
  for 
  the 
  escape 
  of 
  petroleum, 
  and 
  it 
  is 
  surprising 
  

   to 
  find 
  so 
  lew 
  seepages. 
  The 
  best 
  developed 
  of 
  these 
  is 
  on 
  Labrea 
  

   Creek 
  at 
  and 
  near 
  its 
  junction 
  with 
  Rattlesnake 
  Canyon, 
  and 
  is 
  

   typical 
  of 
  the 
  localities 
  noted 
  north 
  of 
  Sisquoc 
  River. 
  The 
  oil 
  seep- 
  

   age 
  is 
  associated 
  with 
  small 
  springs 
  of 
  strongly 
  saline 
  and 
  sulphurous 
  

   water,. 
  and 
  the 
  oil 
  has 
  exuded 
  along 
  the 
  bedding 
  planes 
  of 
  the 
  Mon- 
  

   terey 
  shales, 
  here 
  thrown 
  into 
  a 
  pronounced 
  anticline 
  which 
  has 
  been 
  

   flexed 
  in 
  such 
  a 
  manner 
  as 
  to 
  open 
  out 
  the 
  laminae 
  of 
  the 
  shale 
  and 
  

   thus 
  give 
  better 
  opportunity 
  for 
  the 
  passage 
  of 
  oil. 
  Two 
  wells 
  have 
  

   been 
  sunk 
  here, 
  but 
  they 
  are 
  shallow 
  and 
  offer 
  no 
  additional 
  data. 
  

  

  The 
  following 
  is 
  a 
  brief 
  statement 
  of 
  the 
  asphalt 
  seepages 
  and 
  brea 
  

   deposits 
  occurring 
  in 
  the 
  San 
  Rafael 
  Mountains: 
  

  

  1. 
  Branch 
  of 
  upper 
  Tepusquet 
  Creek. 
  Slight 
  seepage 
  in 
  bed 
  of 
  creek 
  three-fourths 
  

   of 
  a 
  mile 
  above 
  junction 
  with 
  main 
  stream. 
  At 
  anticlinal 
  axis. 
  Has 
  been 
  located. 
  

  

  2. 
  On 
  Colson 
  Fork 
  of 
  Tepusquet 
  Crock. 
  Black 
  bituminous 
  streaks, 
  veinlete, 
  and 
  

   pockets, 
  associated 
  with 
  calcareous 
  shales 
  which 
  are 
  considerably 
  folded 
  on 
  a 
  minor 
  

   scale. 
  This 
  also 
  has 
  been 
  located. 
  

  

  3. 
  Labrea 
  Creek, 
  at 
  and 
  near 
  junction 
  with 
  Rattlesnake 
  Canyon. 
  

  

  4. 
  Sisquoc 
  dairy. 
  Seepage 
  and 
  asphaltic 
  sands 
  .along 
  sharply 
  defined 
  anticline 
  

   which 
  is 
  obscured 
  by 
  later 
  material. 
  Well 
  sunk 
  here, 
  but 
  no 
  record 
  available. 
  

  

  5. 
  Sisquoc 
  River 
  t 
  one-half 
  mile 
  below 
  Round 
  Corral 
  Canyon. 
  Slight 
  seepage 
  from 
  

   steeply 
  inclined 
  Monterey 
  shale. 
  (Shown 
  in 
  PL 
  III, 
  B, 
  p. 
  34.) 
  

  

  6. 
  Fugler 
  Point, 
  1 
  mile 
  north 
  of 
  Gary. 
  Veins 
  of 
  asphaltum, 
  parallel 
  in 
  a 
  general 
  

   way 
  to 
  the 
  bedding, 
  which 
  here 
  dips 
  25° 
  SW., 
  intrude 
  the 
  fossiliferous 
  Fernando 
  

   (lower 
  Pliocene 
  portion). 
  A 
  shaft 
  has 
  been 
  sunk 
  here 
  a 
  few 
  feet 
  for 
  the 
  removal 
  of 
  

   the 
  asphaltum. 
  

  

  7. 
  Alcatraz 
  mine, 
  3$ 
  miles 
  east 
  of 
  Sisquoc 
  post-office. 
  Vast 
  deposits 
  of 
  asphaltum, 
  

   from 
  a 
  lew 
  feet 
  to 
  200 
  foot 
  or 
  more 
  in 
  thickness, 
  lie 
  unconformably 
  above 
  the 
  steeply 
  

   dipping 
  Monterey 
  shales 
  over 
  large 
  areas 
  in 
  the 
  general 
  region 
  of 
  the 
  mine. 
  These 
  

   deposits 
  have 
  been 
  mined 
  on 
  a 
  large 
  scale 
  at 
  one 
  piace, 
  but 
  at 
  present 
  the 
  plant 
  is 
  

   idle. 
  The 
  mine 
  is 
  shown 
  in 
  PL 
  VIII, 
  A. 
  

  

  8. 
  Zaca 
  Canyon, 
  5 
  miles 
  southeast 
  of 
  Sisquoc 
  post-office. 
  Deposits 
  similar 
  to 
  those 
  

   at 
  the 
  Alcatraz 
  mine 
  arc 
  found 
  on 
  both 
  sides 
  of 
  La 
  Zaca 
  Creek 
  where 
  it 
  debouches 
  

   from 
  its 
  narrow 
  mountain 
  canyon 
  into 
  the 
  broad 
  valley 
  carved 
  by 
  it 
  through 
  the 
  

   hilly 
  country. 
  

  

  9. 
  Sisquoc 
  Ridge, 
  1\ 
  miles 
  north 
  of 
  Sisquoc 
  post-office. 
  A 
  small 
  but 
  significant 
  

   area 
  similar 
  in 
  occurrence 
  to 
  the 
  two 
  preceding. 
  This 
  area 
  overlies 
  the 
  axis 
  of 
  an 
  

   anticline 
  in 
  the 
  Monterey 
  shale. 
  

  

  

  