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  GEOLOGY. 
  53 
  

  

  Barbara 
  County, 
  where 
  it 
  was 
  deposited 
  in 
  the 
  old 
  basin 
  between 
  the 
  

   Santa 
  Ynez 
  and 
  San 
  Rafael 
  ranges. 
  It 
  covers 
  up 
  the 
  Monterey 
  

   over 
  the 
  greater 
  part 
  of 
  the 
  basin, 
  and 
  as 
  its 
  structure 
  in 
  most 
  places 
  

   there 
  conforms 
  approximately 
  to 
  that 
  of 
  the 
  Monterey, 
  it 
  is 
  a 
  fairly 
  

   good 
  key 
  to 
  the 
  folding 
  that 
  has 
  taken 
  place 
  in 
  this 
  underlying 
  

   formation. 
  The 
  relation 
  between 
  the 
  Monterey 
  and 
  Fernando 
  is 
  of 
  

   a 
  somewhat 
  perplexing 
  nature. 
  An 
  unconformity 
  in 
  dip 
  between 
  

   the 
  two 
  was 
  not 
  to 
  be 
  definitely 
  made 
  out 
  on 
  examination 
  of 
  the 
  

   exposed 
  contact 
  in 
  any 
  part 
  of 
  the 
  central 
  basin, 
  because 
  of 
  the 
  

   fact 
  that 
  the 
  Monterey 
  and 
  Fernando 
  were 
  subjected 
  practically 
  to 
  

   the 
  same 
  movements 
  over 
  a 
  large 
  part 
  of 
  the 
  region. 
  Lithologic 
  

   similarity 
  of 
  parts 
  of 
  the 
  Fernando 
  to 
  the 
  Monterey 
  is 
  also 
  an 
  obstacle 
  

   to 
  their 
  differentiation. 
  But 
  pebbles 
  of 
  Monterey 
  shale 
  and 
  flint, 
  

   showing 
  here 
  and 
  there 
  pholas 
  borings 
  and 
  giving 
  evidence 
  of 
  marine 
  

   deposition, 
  are 
  abundant 
  in 
  the 
  Fernando. 
  In 
  fact, 
  the 
  greater 
  part 
  

   of 
  the 
  coarse 
  detrital 
  material 
  of 
  the 
  Fernando 
  conglomerate 
  is 
  

   derived 
  from 
  the 
  Monterey, 
  proving 
  that 
  its 
  period 
  of 
  deposition 
  

   was 
  one 
  of 
  erosion 
  in 
  the 
  previously 
  deposited 
  shale, 
  that 
  it 
  followed 
  

   the 
  uplift 
  above 
  sea 
  level 
  of 
  a 
  portion 
  of 
  the 
  Monterey, 
  and 
  that 
  it 
  

   was 
  subsequent 
  to 
  the 
  formation 
  of 
  the 
  flint 
  in 
  that 
  shale 
  series. 
  

   The 
  importance 
  of 
  the 
  break 
  between 
  the 
  two 
  is 
  indicated 
  by 
  the 
  

   change 
  in 
  character 
  of 
  the 
  deposits 
  from 
  organic, 
  probably 
  deep- 
  

   water 
  sediments 
  almost 
  free 
  from 
  erosional 
  debris 
  to 
  sandy 
  and 
  

   gravelly 
  deposits 
  derived 
  from 
  the 
  wearing 
  away 
  of 
  hard 
  land 
  areas. 
  

   This 
  change 
  was 
  hardly 
  as 
  marked 
  as 
  that 
  occurring 
  in 
  the 
  reverse 
  

   order 
  at 
  the 
  close 
  of 
  Vaqueros 
  time, 
  although 
  it 
  accompanied 
  what 
  

   was 
  probably 
  a 
  greater 
  time 
  and 
  structural 
  break. 
  The 
  apparent 
  

   structural 
  conformity 
  between 
  the 
  Monterey 
  and 
  Fernando 
  at 
  most 
  

   places 
  within 
  the 
  basin 
  region 
  is 
  probably 
  due 
  to 
  the 
  previously 
  

   almost 
  undisturbed 
  attitude 
  of 
  the 
  shale 
  upon 
  which 
  the 
  Fernando 
  

   was 
  laid 
  down 
  and 
  the 
  subsequent 
  disturbance 
  of 
  both 
  formations 
  

   at 
  the 
  same 
  time. 
  But 
  remnants 
  of 
  the 
  Fernando 
  left 
  around 
  the 
  

   border 
  exhibit 
  less 
  conformity 
  with 
  the 
  underlying 
  Monterey, 
  owing 
  

   doubtless 
  to 
  the 
  fact 
  that 
  the 
  shale 
  of 
  the 
  latter 
  was 
  upheaved 
  around 
  

   the 
  edges 
  of 
  the 
  basin 
  to 
  form 
  the 
  mountains 
  bordering 
  it 
  during 
  

   the 
  period 
  intervening 
  between 
  the 
  close 
  of 
  Monterey 
  time 
  and 
  the 
  

   beginning 
  of 
  deposition 
  of 
  the 
  Fernando. 
  

  

  The 
  chief 
  importance 
  of 
  the 
  Fernando 
  in 
  connection 
  with 
  studies 
  

   of 
  this 
  oil 
  field 
  is 
  derived 
  from 
  the 
  facts 
  that 
  it 
  hides 
  the 
  oil-bearing 
  

   formation 
  over 
  a 
  wide 
  area; 
  that 
  it 
  affords 
  through 
  its 
  structure, 
  

   however, 
  a 
  clue 
  to 
  the 
  structure 
  of 
  the 
  underlying 
  Monterey; 
  and 
  

   that 
  it 
  acts 
  as 
  a 
  reservoir 
  for 
  oil 
  (Arroyo 
  Grande 
  field) 
  and 
  as 
  a 
  recep- 
  

   tacle 
  for 
  escaping 
  bituminous 
  material. 
  In 
  the 
  last-mentioned 
  way 
  

   it 
  gives 
  origin 
  to 
  asphalt 
  deposits 
  of 
  economic 
  value 
  and 
  to 
  cappings 
  

   of 
  hard 
  asphalt 
  that 
  may 
  be 
  of 
  significance 
  as 
  an 
  aid 
  in 
  the 
  retention 
  

   of 
  the 
  oil 
  within 
  the 
  Monterey. 
  

  

  