﻿48 
  SANTA 
  MARIA 
  OIL 
  DISTRICT, 
  CALIFORNIA. 
  

  

  METAMORPHISM 
  OF 
  THE 
  SHALE 
  BY 
  COMBUSTION. 
  

  

  At 
  many 
  different 
  places 
  in 
  the 
  Santa 
  Maria 
  district 
  and 
  elsewhere 
  

   the 
  oil-bearing 
  shale 
  has 
  been 
  burnt 
  to 
  a 
  pink 
  or 
  deep 
  brick-red 
  color, 
  

   or 
  turned 
  into 
  a 
  hard 
  vesicular 
  rock 
  like 
  scoriaceous 
  lava, 
  as 
  shown 
  

   in 
  PL 
  V, 
  B, 
  p. 
  36. 
  This 
  metamorphism 
  is 
  due 
  to 
  the 
  combustion 
  of 
  

   the 
  hydrocarbon 
  content. 
  Though 
  the 
  combustion 
  is 
  usually 
  local 
  

   in 
  its 
  effects, 
  the 
  number 
  and 
  wide 
  distribution 
  of 
  the 
  occurrences 
  of 
  

   burnt 
  shale 
  lend 
  importance 
  to 
  the 
  phenomenon. 
  Such 
  altered 
  shale 
  

   is 
  of 
  some 
  value 
  as 
  indicating 
  where 
  the 
  rock 
  has 
  been 
  bituminous 
  

   and 
  where 
  the 
  conditions 
  have 
  favored 
  the 
  occurrence 
  of 
  seepages. 
  

  

  LOCALITIES 
  WHERE 
  THE 
  SHALE 
  IS 
  AT 
  PRESENT 
  BURNING. 
  

  

  A 
  number 
  of 
  localities 
  have 
  been 
  observed 
  at 
  which 
  combustion 
  

   is 
  at 
  present 
  or 
  has 
  been 
  in 
  recent 
  years 
  in 
  progress 
  within 
  the 
  Mon- 
  

   terey 
  shale. 
  One 
  of 
  these 
  is 
  on 
  the 
  north 
  side 
  of 
  Graciosa 
  Ridge, 
  

   south 
  of 
  the 
  Santa 
  Maria 
  Valley, 
  near 
  the 
  Rice 
  ranch 
  oil 
  well 
  No. 
  1. 
  

   When 
  this 
  locality 
  was 
  visited 
  by 
  the 
  writers 
  early 
  in 
  the 
  autumn 
  

   of 
  1906, 
  a 
  fire 
  was 
  burning 
  underground 
  in 
  the 
  shale, 
  causing 
  a 
  smoke 
  

   of 
  disagreeable 
  odor 
  to 
  issue 
  from 
  the 
  surface 
  and 
  making 
  the 
  ground 
  

   hot 
  over 
  an 
  area 
  of 
  many 
  square 
  yards. 
  Oil 
  was 
  oozing 
  up 
  at 
  various 
  

   points 
  near 
  by, 
  and 
  the 
  ground 
  was 
  heated 
  in 
  the 
  neighborhood 
  of 
  

   all 
  these 
  seepages. 
  The 
  holes 
  from 
  which 
  vapor 
  issued 
  were 
  coated 
  

   with 
  delicate 
  crystals 
  of 
  sulphur. 
  At 
  the 
  point 
  where 
  the 
  burning 
  

   was 
  actually 
  going 
  on 
  and 
  all 
  about 
  in 
  the 
  vicinity, 
  for 
  a 
  distance 
  

   of 
  several 
  hundred 
  feet 
  in 
  some 
  directions, 
  the 
  shale 
  was 
  altered 
  to 
  

   a 
  bright-red 
  color, 
  or 
  baked 
  almost 
  to 
  the 
  hardness 
  of 
  compact 
  igneous 
  

   rock, 
  or 
  rendered 
  vesicular 
  like 
  lava. 
  

  

  There 
  can 
  be 
  no 
  doubt 
  that 
  this 
  fire 
  was 
  supported 
  by 
  the 
  bitu- 
  

   minous 
  material 
  in 
  the 
  shale, 
  and 
  it 
  was 
  probably 
  started 
  by 
  brush 
  

   fires, 
  though 
  these 
  had 
  occurred 
  a 
  good 
  many 
  months 
  before, 
  as 
  

   shown 
  by 
  the 
  new 
  growth 
  of 
  the 
  bushes. 
  It 
  was 
  said 
  that 
  there 
  

   was 
  a 
  brush 
  fire 
  about 
  January 
  1, 
  1906, 
  which 
  started 
  the 
  fire 
  in 
  the 
  

   shale, 
  and 
  that 
  futile 
  attempts 
  to 
  put 
  it 
  out 
  by 
  dumping 
  dirt 
  to 
  

   smother 
  it 
  had 
  been 
  made 
  ever 
  since 
  that 
  time. 
  It 
  seems 
  likely, 
  

   however, 
  that 
  this 
  same 
  fire 
  has 
  been 
  in 
  progress 
  for 
  several 
  years. 
  

   This 
  likelihood 
  is 
  borne 
  out 
  by 
  other 
  accounts. 
  It 
  is 
  stated 
  that 
  

   sometimes 
  during 
  the 
  course 
  of 
  brush 
  fires 
  on 
  the 
  hills 
  sudden 
  darts 
  

   of 
  flames 
  may 
  be 
  seen 
  at 
  night 
  from 
  a 
  considerable 
  distance 
  — 
  the 
  

   result 
  of 
  the 
  setting 
  on 
  fire 
  of 
  gas 
  escaping 
  from 
  the 
  rocks. 
  

  

  Other 
  cases 
  of 
  burning 
  in 
  the 
  shale 
  have 
  been 
  observed 
  in 
  recent 
  

   years 
  at 
  the 
  San 
  Marcos 
  ranch 
  in 
  the 
  Santa 
  Ynez 
  Valley, 
  and 
  at 
  the 
  

   mouth 
  of 
  Rincon 
  Creek, 
  on 
  the 
  coast 
  near 
  Santa 
  Barbara, 
  as 
  de- 
  

   scribed 
  by 
  H. 
  C. 
  Ford.° 
  The 
  phenomena 
  exhibited 
  resemble 
  those 
  

  

  a 
  Bull. 
  Santa 
  Barbara 
  Soc. 
  Nat. 
  Hist., 
  vol. 
  1, 
  No. 
  2, 
  October, 
  1890. 
  

  

  