﻿64 
  SANTA 
  MARTA 
  OIL 
  DISTRICT, 
  CALIFORNIA. 
  

  

  hills 
  was 
  probably 
  at 
  least 
  partly 
  covered 
  during 
  the 
  uplift 
  of 
  the 
  

   coast 
  by 
  marine 
  terrace 
  deposits 
  similar 
  to 
  those 
  found 
  elsewhere 
  in 
  

   the 
  region, 
  these 
  being 
  later 
  buried 
  by 
  the 
  gathering 
  wind-blown 
  

   sand. 
  Recent 
  marine 
  shells 
  are 
  widely 
  scattered 
  over 
  the 
  surface 
  

   of 
  this 
  sand, 
  but 
  are 
  not 
  considered 
  by 
  the 
  writers 
  as 
  indicating 
  its 
  

   marine 
  origin. 
  They 
  were 
  probably 
  carried 
  there 
  by 
  Indians 
  or 
  

   birds. 
  

  

  South 
  of 
  the 
  Casmalia 
  Hills, 
  where 
  the 
  coast 
  is 
  open 
  to 
  the 
  

   winds, 
  sand 
  dunes 
  are 
  continually 
  forming 
  and 
  covering 
  up 
  the 
  ter- 
  

   race 
  deposits. 
  The 
  sand 
  is 
  not 
  retarded 
  by 
  an 
  inland 
  barrier, 
  how- 
  

   ever, 
  as 
  on 
  the 
  north 
  of 
  the 
  hills, 
  and 
  no 
  such 
  vast 
  deposit 
  has 
  been 
  

   formed. 
  The 
  sand 
  is 
  continually 
  being 
  carried 
  into 
  the 
  interior 
  

   valleys 
  and 
  spread 
  thinly 
  over 
  a 
  wide 
  area. 
  

  

  ALLUVIUM. 
  

  

  All 
  the 
  valleys 
  of 
  this 
  region 
  contain 
  a 
  certain 
  amount 
  of 
  alluvial 
  

   material 
  and 
  stream 
  gravels, 
  which 
  reach 
  in 
  many 
  localities 
  a 
  thick- 
  

   ness 
  of 
  50 
  feet 
  or 
  more. 
  In 
  some 
  places 
  the 
  deposit 
  is 
  earthy, 
  in 
  

   others 
  sandy 
  earth, 
  and 
  in 
  still 
  others 
  pure 
  sand, 
  gravel, 
  or 
  clay. 
  

   It 
  is 
  as 
  a 
  rule 
  horizontally 
  stratified. 
  Recent 
  deposits 
  of 
  this 
  charac- 
  

   ter 
  attain 
  considerable 
  extent 
  in 
  the 
  wide 
  valleys, 
  but 
  it 
  is 
  not 
  easy 
  

   to 
  distinguish 
  them 
  from 
  Quaternary 
  deposits 
  of 
  different 
  age 
  or 
  of 
  

   somewhat 
  different 
  origin. 
  They 
  are 
  mapped 
  as 
  distinct 
  only 
  in 
  the 
  

   larger 
  valleys 
  and 
  the 
  contact 
  lines 
  are 
  arbitrary. 
  Practically 
  all 
  

   the 
  hills 
  and 
  valleys 
  within 
  the 
  territory 
  mapped 
  have 
  a 
  covering 
  

   of 
  soil. 
  

  

  IGNEOUS 
  ROCKS. 
  

   GENERAL 
  STATEMENT. 
  

  

  The 
  formations 
  in 
  this 
  region 
  are 
  chiefly 
  of 
  sedimentary 
  origin, 
  

   but 
  eruptive 
  and 
  intrusive 
  igneous 
  rocks 
  of 
  various 
  ages 
  appear. 
  

   These 
  are 
  all 
  basic 
  in 
  composition. 
  Layers 
  of 
  volcanic 
  ash 
  high 
  in 
  

   silica 
  interbedded 
  with 
  the 
  Monterey 
  are 
  discussed 
  with 
  the 
  sedi- 
  

   mentary 
  series 
  (p. 
  37). 
  The 
  center 
  for 
  igneous 
  rocks 
  is 
  in 
  the 
  region 
  

   around 
  Point 
  Sal 
  of 
  which 
  Fairbanks 
  made 
  a 
  special 
  study, 
  and 
  

   the 
  statements 
  here 
  made 
  in 
  regard 
  to 
  the 
  igneous 
  rocks 
  of 
  that 
  region 
  

   are 
  based 
  largely 
  on 
  his 
  description." 
  

  

  IGNEOUS 
  ROCKS 
  OF 
  PRE-MONTEREY 
  AGE. 
  

  

  Fairbanks 
  describes 
  a 
  small 
  intrusion 
  of 
  basalt 
  having 
  a 
  laccolithic 
  

   appearance 
  in 
  the 
  Knoxville 
  (lower 
  Cretaceous) 
  shales 
  north 
  of 
  

   Mount 
  Lospe, 
  in 
  the 
  Casmalia 
  Hills, 
  and 
  a 
  large 
  neighboring 
  area 
  

   of 
  spheroidal 
  basalt 
  that 
  he 
  is 
  certain 
  is 
  older 
  than 
  the 
  Monterey 
  

  

  a 
  Fairbanks, 
  H. 
  W., 
  The 
  geology 
  of 
  Point 
  Sal: 
  Bull. 
  Dept. 
  Geology, 
  Univ. 
  California, 
  vol. 
  3, 
  1896, 
  

   pp. 
  1-92. 
  

  

  