﻿26 
  SANTA 
  MARIA 
  OIL 
  DISTRICT, 
  CALIFORNIA. 
  

  

  the 
  long 
  dry 
  season 
  almost 
  complete 
  evaporation 
  of 
  surface 
  moisture 
  

   takes 
  place, 
  and 
  there 
  is 
  little 
  erosion 
  through 
  the 
  aid 
  of 
  water. 
  

   Throughout 
  the 
  latter 
  part 
  of 
  the 
  Quaternary 
  period 
  the 
  rate 
  of 
  ero- 
  

   sion 
  has 
  probably 
  been 
  slow. 
  

  

  CLIMATE 
  AND 
  VEGETATION. 
  

  

  The 
  climate 
  of 
  this 
  area 
  is 
  that 
  of 
  the 
  coastal 
  region 
  of 
  California. 
  

   It 
  is 
  equable 
  the 
  whole 
  year 
  round, 
  excessive 
  heat 
  or 
  cold 
  being 
  

   very 
  rare. 
  The 
  days 
  are 
  mild, 
  the 
  nights 
  chilly. 
  The 
  region 
  is 
  sub- 
  

   ject 
  to 
  the 
  inroads 
  of 
  heavy 
  fogs 
  and 
  driving 
  winds 
  from 
  the 
  open 
  

   ocean, 
  but 
  this 
  is 
  true 
  to 
  a 
  lesser 
  degree 
  in 
  the 
  eastern 
  angle 
  of 
  the 
  

   basin, 
  where 
  there 
  are 
  protecting 
  hills 
  on 
  all 
  sides. 
  The 
  winds 
  

   blow 
  very 
  strongly 
  from 
  the 
  west 
  and 
  northwest 
  up 
  the 
  radiating 
  

   valleys 
  that 
  open 
  to 
  the 
  coast. 
  The 
  region 
  is 
  subject 
  to 
  earth- 
  

   quakes, 
  some 
  of 
  which 
  would 
  seem 
  to 
  be 
  of 
  local 
  origin. 
  

  

  The 
  vegetation 
  in 
  the 
  northern 
  part 
  of 
  Santa 
  Barbara 
  County 
  is 
  

   open, 
  as 
  in 
  the 
  neighboring 
  portions 
  of 
  California. 
  There 
  are 
  almost 
  

   no 
  dense 
  groves 
  of 
  trees, 
  most 
  of 
  the 
  hills 
  being 
  sparsely 
  clothed 
  

   with 
  a 
  scattering 
  growth 
  of 
  small 
  trees, 
  usually 
  live 
  and 
  white 
  oaks, 
  

   and 
  bushes, 
  or 
  else 
  entirely 
  bare, 
  except 
  for 
  sagebrush 
  and 
  grass. 
  

   The 
  wide 
  terraces 
  and 
  hills 
  of 
  soft 
  sand 
  are 
  commonly 
  overgrown 
  

   with 
  so-called 
  tarw 
  r 
  eed 
  and 
  are 
  otherwise 
  almost 
  bare. 
  In 
  the 
  val- 
  

   leys 
  near 
  the 
  coast 
  grow 
  many 
  willows; 
  in 
  the 
  more 
  protected 
  val- 
  

   leys 
  farther 
  inland 
  thrive 
  large 
  sycamores, 
  cottonwoods, 
  and 
  live 
  

   and 
  white 
  oaks. 
  The 
  steep 
  slopes 
  of 
  the 
  San 
  Rafael 
  Range 
  are 
  

   sparsely 
  set 
  with 
  small 
  oaks, 
  pines, 
  and 
  yuccas, 
  and, 
  like 
  those 
  of 
  

   the 
  Santa 
  Ynez 
  Range, 
  are 
  covered 
  in 
  parts 
  by 
  dense 
  thickets 
  of 
  

   undergrowth. 
  

  

  The 
  vegetation 
  of 
  the 
  hill 
  ranges 
  of 
  the 
  basin 
  region 
  is 
  typically 
  

   illustrated 
  by 
  PL 
  IX 
  (p. 
  80) 
  and 
  of 
  the 
  San 
  Rafael 
  Mountain 
  region 
  

   by 
  PI. 
  VI 
  (p. 
  46). 
  

  

  GEOLOGY. 
  

  

  SEDIMENTARY 
  FORMATIONS. 
  

  

  GENERAL 
  STATEMENT. 
  

  

  The 
  formations 
  involved 
  in 
  the 
  geology 
  of 
  this 
  district 
  (see 
  PI. 
  II) 
  

   include 
  the 
  Franciscan 
  (Jurassic?); 
  Knoxville 
  (lower 
  Cretaceous); 
  

   pre-Monterey 
  rocks 
  (which 
  may 
  include 
  both 
  Cretaceous 
  and 
  older 
  

   Tertiary); 
  Tejon, 
  Sespe, 
  and 
  Vaqueros, 
  undifferentiated 
  (Eocene- 
  

   Miocene); 
  Monterey 
  (middle 
  Miocene) 
  ; 
  Fernando 
  (Miocene-Pliocene- 
  

   Pleistocene) 
  ; 
  and 
  Quaternary. 
  The 
  maximum 
  known 
  thickness 
  of 
  the 
  

   Tertiary 
  and 
  early 
  Quaternary 
  formations 
  combined 
  is 
  13,200 
  feet. 
  

   The 
  following 
  table 
  shows 
  the 
  correlation 
  of 
  these 
  formations 
  with 
  the 
  

  

  