﻿62 
  SANTA 
  MARIA 
  OIL 
  DISTRICT, 
  CALIFORNIA. 
  

  

  be 
  called- 
  is 
  composed 
  of 
  bowlders, 
  pebbles, 
  and 
  fragments 
  of 
  Mon- 
  

   terey 
  flint 
  and 
  shale, 
  besides 
  pebbles 
  of 
  other 
  rocks 
  in 
  smaller 
  quan- 
  

   tity. 
  Some 
  of 
  the 
  pebbles 
  are 
  very 
  much 
  waterworn, 
  but 
  in 
  places 
  

   the 
  number 
  of 
  unworn 
  fragments 
  of 
  shale 
  almost 
  necessitates 
  the 
  use 
  

   of 
  the 
  word 
  "breccia" 
  in 
  describing 
  the 
  deposits. 
  Evidence 
  of 
  bed- 
  

   ding 
  is 
  rarely 
  prominent 
  in 
  the 
  typical 
  terrace 
  deposits, 
  but 
  they 
  

   invariably 
  appear 
  to 
  lie 
  horizontal, 
  seeming 
  to 
  have 
  been 
  little 
  dis- 
  

   turbed 
  by 
  the 
  uplift 
  of 
  the 
  land 
  that 
  brought 
  them 
  to 
  their 
  present 
  

   elevation. 
  

  

  Xo 
  fossils 
  have 
  been 
  found 
  in 
  these 
  deposits, 
  but 
  they 
  contain 
  

   numerous 
  pholas-bored 
  pebbles 
  of 
  Monterey 
  shale, 
  and 
  in 
  places, 
  as 
  

   on 
  Burton 
  Mesa, 
  the 
  Monterey 
  shale 
  itself, 
  upon 
  which 
  the 
  deposits 
  

   lie, 
  has 
  been 
  bored 
  by 
  these 
  marine 
  mollusks. 
  

  

  Many 
  of 
  the 
  cappings 
  formed 
  parallel 
  with 
  the 
  surface 
  through 
  

   hardening 
  by 
  iron 
  oxide 
  have 
  the 
  appearance 
  of 
  being 
  beds 
  with 
  

   appreciable 
  dip, 
  and 
  are 
  therefore 
  misleading. 
  The 
  thickness 
  of 
  the 
  

   coating 
  of 
  Burton 
  Mesa 
  is 
  25 
  or 
  30 
  feet 
  and 
  the 
  cover 
  of 
  the 
  typical 
  

   terrace 
  in 
  other 
  parts 
  of 
  the 
  region 
  has 
  about 
  the 
  same 
  thickness. 
  

   Whether 
  it 
  attains 
  a 
  much 
  greater 
  development 
  than 
  this 
  at 
  any 
  , 
  

   place 
  is 
  hard 
  to 
  tell. 
  These 
  shallow 
  coverings 
  hide 
  considerable 
  areas 
  

   of 
  the 
  Monterey 
  and 
  obscure 
  its 
  structure, 
  but 
  most 
  of 
  the 
  canyons 
  

   that 
  cut 
  into 
  the 
  terraces 
  reveal 
  the 
  presence 
  of 
  the 
  oil-bearing 
  for- 
  

   mation 
  beneath. 
  The 
  thickness 
  of 
  the 
  coatings 
  is 
  not 
  sufficient 
  to 
  

   make 
  a 
  serious 
  difference 
  in 
  the 
  depth 
  to 
  which 
  it 
  is 
  necessary 
  to 
  

   drill 
  for 
  oil. 
  The 
  deposits 
  are 
  economically 
  of 
  importance 
  as 
  reser- 
  

   voirs 
  for 
  the 
  oil 
  escaping 
  from 
  the 
  Monterey 
  shale, 
  and 
  thus 
  they 
  

   give 
  rise 
  to 
  accumulations 
  of 
  asphalt. 
  It 
  is 
  usually 
  impossible 
  to 
  

   tell 
  whether 
  the 
  sand 
  that 
  helps 
  to 
  form 
  the 
  asphalt 
  is 
  a 
  terrace 
  

   deposit 
  or 
  belongs 
  to 
  the 
  Fernando. 
  The 
  terrace 
  sand 
  can 
  not 
  form 
  

   as 
  deep 
  asphalt 
  deposits 
  as 
  those 
  due 
  to 
  the 
  Fernando 
  sand. 
  

  

  In 
  some 
  of 
  the 
  valley 
  fillings 
  above 
  mentioned, 
  as 
  for 
  instance 
  along 
  

   Salsipuedes 
  Creek, 
  and 
  at 
  the 
  west 
  edge 
  of 
  the 
  Santa 
  Maria 
  Valley 
  

   between 
  Guadalupe 
  Lake 
  and 
  the 
  Casmalia 
  Hills, 
  there 
  occur 
  hori- 
  

   zontally 
  bedded 
  deposits 
  of 
  clay, 
  sand, 
  and 
  gravel 
  differing 
  in 
  ap- 
  

   pearance 
  from 
  the 
  terrace 
  deposits 
  and 
  possibly 
  differing 
  in 
  age 
  and 
  

   origin. 
  A 
  good 
  example 
  of 
  an 
  old 
  valley 
  filling 
  w 
  T 
  hich 
  now 
  forms 
  the 
  

   summit 
  of 
  a 
  hill 
  is 
  shown 
  in 
  PL 
  IV, 
  B 
  (p. 
  36). 
  It 
  consists 
  of 
  a 
  sandy 
  

   and 
  earthy 
  material 
  through 
  which 
  rock 
  fragments 
  and 
  pebbles 
  are 
  

   scattered. 
  It 
  illustrates 
  the 
  usual 
  unconformity 
  of 
  the 
  post-Fernando 
  

   deposits 
  with 
  the 
  older 
  formations. 
  The 
  low 
  hills 
  in 
  the 
  region 
  of 
  

   Santa 
  Ynez 
  are 
  formed 
  largely 
  of 
  horizontal 
  beds 
  of 
  fine 
  gravel 
  

   unlike 
  the 
  Pleistocene 
  deposits 
  found 
  elsewhere. 
  These 
  exhibit 
  in 
  

   one 
  place 
  an 
  appearance 
  of 
  being 
  tilted, 
  though 
  this 
  may 
  be 
  due 
  to 
  

   cross-bedding. 
  

  

  