﻿22 
  SANTA 
  .MAUI 
  A 
  OIL 
  DISTRICT, 
  CALIFORNIA. 
  

  

  Longitudinal 
  trough 
  running 
  for 
  miles 
  parallel 
  with 
  this 
  range 
  and 
  the 
  

   Los 
  Alamos 
  Valley 
  and 
  cutting 
  across 
  the 
  ends 
  of 
  the 
  above-mentioned 
  

   ridges 
  at 
  right 
  angles 
  to 
  them, 
  at 
  a 
  distance 
  of 
  one-half 
  to 
  1 
  mile 
  from 
  

   the 
  valley. 
  It 
  notches 
  all 
  the 
  ridges 
  and 
  leaves 
  an 
  individual 
  row 
  of 
  

   knobs 
  100 
  to 
  200 
  foot 
  in 
  relief 
  bordering 
  the 
  valley. 
  This 
  depression 
  

   is 
  not 
  a 
  continuous 
  drainage 
  feature, 
  but 
  is 
  stratigraphically 
  of 
  impor- 
  

   tance 
  as 
  approximately 
  marking 
  the 
  contact 
  between 
  the 
  Monterey 
  

   shale 
  and 
  the 
  loose 
  Fernando 
  sand. 
  On 
  the 
  south 
  side 
  of 
  the 
  summit 
  

   of 
  the 
  Purisima 
  Hills 
  the 
  lateral 
  ridges 
  extend 
  a 
  long 
  way 
  with 
  a 
  uni- 
  

   form 
  gentle 
  slope, 
  like 
  remnants 
  of 
  an 
  eroded 
  inclined 
  plateau. 
  At 
  

   their 
  base, 
  some 
  miles 
  from 
  the 
  summit, 
  and 
  usually 
  from 
  500 
  to 
  1,000 
  

   feel 
  below, 
  these 
  southern 
  slopes 
  merge 
  into 
  an 
  undulating 
  hilly 
  

   plateau 
  that 
  has 
  the 
  appearance 
  of 
  being 
  buried 
  under 
  soft 
  recent 
  

   sand. 
  The 
  range 
  is 
  broadest 
  at 
  the 
  east 
  end, 
  where 
  it 
  consists 
  of 
  a 
  

   number 
  of 
  parallel 
  ridges. 
  The 
  point 
  of 
  convergence 
  of 
  some 
  of 
  these 
  

   is 
  lledrock 
  Mountain, 
  which 
  is 
  1 
  ,968 
  feet 
  high 
  and 
  the 
  highest 
  summit 
  

   in 
  these 
  hills. 
  Thence 
  westward 
  the 
  hilly 
  zone 
  narrows 
  into 
  a 
  single 
  

   central 
  ridge 
  and 
  its 
  offshoots, 
  and 
  gradually 
  pinches 
  out, 
  finally 
  giv- 
  

   ing 
  place 
  on 
  the 
  south 
  and 
  west 
  to 
  a 
  broad 
  terrace 
  in 
  which 
  its 
  hilly 
  

   character 
  is 
  lost. 
  The 
  summit 
  of 
  the 
  main 
  ridge 
  of 
  the 
  Purisima 
  

   Hills 
  west 
  of 
  Redrock 
  Mountain 
  gradually 
  declines 
  in 
  height 
  and 
  for 
  

   most 
  of 
  the 
  way 
  it 
  is 
  remarkably 
  even, 
  the 
  elevation 
  varying 
  between 
  

   1,200 
  and 
  1,000 
  feet. 
  At 
  the 
  elevation 
  of 
  1,000 
  feet 
  it 
  grades 
  into 
  

   the 
  smooth 
  terrace 
  called 
  Burton 
  Mesa. 
  s 
  

  

  BURTON 
  MESA. 
  

  

  Burton 
  Mesa 
  is 
  a 
  marine 
  terrace 
  covering 
  more 
  than 
  50 
  square 
  miles, 
  

   which 
  slopes, 
  with 
  an 
  average 
  gradient 
  of 
  2 
  J 
  per 
  cent, 
  away 
  from 
  the 
  

   west 
  end 
  of 
  the 
  Purisima 
  Hills, 
  reaching 
  the 
  sea 
  within 
  1\ 
  miles. 
  It 
  

   is 
  composed 
  of 
  Monterey 
  shale, 
  in 
  the 
  main 
  rather 
  gently 
  folded, 
  

   which 
  has 
  been 
  planed 
  off 
  and 
  covered 
  with 
  a 
  thickness 
  of 
  about 
  25 
  

   feet 
  of 
  horizontal 
  gravel 
  and 
  loose 
  sand. 
  From 
  the 
  elevation 
  of 
  1,000 
  

   feet, 
  where 
  the 
  continuous 
  sheet 
  of 
  sand 
  overlaps 
  on 
  the 
  end 
  of 
  the 
  Puri- 
  

   sima 
  ridge, 
  down 
  to 
  the 
  600-foot 
  level 
  the 
  distance 
  in 
  a 
  west-south- 
  

   west 
  direction 
  is 
  three-fourths 
  of 
  a 
  mile 
  and 
  the 
  slope 
  10 
  per 
  cent. 
  

   Within 
  the 
  next 
  three-fourths 
  of 
  a 
  mile 
  a 
  drop 
  of 
  100 
  feet 
  occurs, 
  the 
  

   slope 
  being 
  2\ 
  per 
  cent. 
  Beyond 
  lies 
  the 
  main 
  level 
  stretch 
  of 
  the 
  

   plateau 
  for 
  a 
  distance 
  of 
  5 
  miles, 
  with 
  no 
  greater 
  slope 
  than 
  three- 
  

   fourths 
  of 
  1 
  per 
  cent 
  until 
  the 
  elevation 
  of 
  300 
  feet 
  is 
  reached, 
  in 
  the 
  

   southwest 
  corner 
  of 
  the 
  mesa, 
  where 
  there 
  is 
  an 
  abrupt 
  change 
  to 
  a 
  

   10 
  per 
  cent 
  slope, 
  the 
  distance 
  down 
  to 
  elevation 
  100 
  feet 
  being 
  only 
  

   one- 
  third 
  of 
  a 
  mile. 
  Below 
  the 
  100-foot 
  level 
  there 
  is 
  a 
  bench 
  with 
  

   a 
  3 
  per 
  cent 
  grade 
  as 
  far 
  as 
  the 
  edge 
  of 
  the 
  cliff 
  which 
  faces 
  the 
  sea, 
  

   and 
  which 
  is 
  in 
  most 
  places 
  about 
  25 
  feet 
  above 
  the 
  water. 
  North 
  

  

  