﻿GEOLOGY. 
  39 
  

  

  the 
  same 
  appearance, 
  as 
  if 
  formed 
  of 
  the 
  same 
  materials, 
  but 
  com- 
  

   pacting 
  and 
  crushing 
  seem 
  to 
  have 
  gone 
  a 
  little 
  further 
  so 
  as 
  to 
  obscure 
  

   the 
  organic 
  remains. 
  Almost 
  all 
  the 
  shale 
  of 
  the 
  upper 
  division 
  of 
  

   the 
  Monterey 
  contains 
  diatom 
  remains 
  where 
  it 
  has 
  not 
  undergone 
  

   alteration 
  into 
  the 
  hard 
  varieties. 
  The 
  same 
  is 
  true 
  of 
  the 
  soft 
  

   shale 
  wherever 
  it 
  occurs 
  in 
  the 
  lower 
  portion 
  of 
  the 
  formation, 
  the 
  

   most 
  notable 
  example 
  being 
  at 
  the 
  very 
  base 
  of 
  the 
  Monterey 
  on 
  the 
  

   San 
  Julian 
  ranch 
  east 
  of 
  the 
  junction 
  of 
  Salsipuedes 
  and 
  El 
  Jaro 
  

   creeks, 
  where 
  it 
  is 
  associated 
  with 
  hard 
  flint 
  and 
  limestone 
  immedi- 
  

   ately 
  overlying 
  the 
  fossiliferous 
  limestone 
  and 
  conglomerate 
  of 
  the 
  

   Vaqueros. 
  There 
  the 
  shale 
  is 
  earthy, 
  pure 
  white, 
  and 
  full 
  of 
  diatoms. 
  

  

  When 
  the 
  shale 
  has 
  undergone 
  alteration 
  and 
  hardening 
  into 
  the 
  

   porcelaneous 
  and 
  flinty 
  varieties 
  the 
  constituent 
  organic 
  remains 
  are 
  

   usually 
  obscured, 
  but 
  here 
  and 
  there 
  even 
  in 
  these 
  the 
  impressions 
  

   may 
  be 
  found 
  preserved. 
  Usually 
  an 
  examination 
  under 
  the 
  micro- 
  

   scope 
  reveals 
  scattering 
  circular 
  and 
  oval 
  areas, 
  of 
  slightly 
  different 
  

   composition 
  or 
  character 
  from 
  the 
  surrounding 
  rock, 
  that 
  look 
  as 
  if 
  

   they 
  might 
  represent 
  the 
  forms 
  of 
  organisms. 
  In 
  speaking 
  of 
  the 
  

   exposure 
  of 
  Monterey 
  rocks 
  between 
  the 
  mouth 
  of 
  Schumann 
  Canyon 
  

   and 
  Lions 
  Head 
  on 
  the 
  southern 
  flank 
  of 
  the 
  Casmalia 
  Hills, 
  H. 
  W. 
  

   Fairbanks 
  says: 
  a 
  "The 
  basal 
  portion 
  of 
  the 
  series 
  is 
  composed 
  chiefly 
  

   of 
  clear, 
  flinty 
  rocks, 
  showing 
  abundant 
  remains 
  of 
  organisms 
  visible 
  

   to 
  the 
  unaided 
  eye." 
  And 
  in 
  speaking 
  of 
  the 
  harder 
  varieties 
  of 
  

   Monterey 
  shale 
  in 
  general 
  of 
  the 
  Point 
  Sal 
  region 
  he 
  says: 
  6 
  "When 
  

   examined 
  with 
  the 
  hand 
  lens 
  much 
  of 
  the 
  rock 
  is 
  seen 
  to 
  be 
  thickly 
  

   specked 
  with 
  little 
  round 
  dots, 
  averaging, 
  perhaps, 
  a 
  millimeter 
  in 
  

   diameter. 
  Under 
  the 
  microscope 
  * 
  * 
  * 
  the 
  circular 
  areas 
  did 
  

   not 
  appear 
  as 
  numerous 
  as 
  in 
  the 
  hand 
  specimen, 
  and 
  were 
  only 
  

   faintly 
  distinguished 
  by 
  clearer 
  polarization." 
  

  

  Aside 
  from 
  the 
  diatoms 
  the 
  rocks 
  of 
  the 
  Monterey-contain 
  remains 
  

   of 
  minute 
  Foraminifera, 
  which 
  have 
  calcareous 
  frames, 
  and 
  Radio- 
  

   laria, 
  which 
  secrete 
  silica 
  to 
  form 
  their 
  tests. 
  The 
  latter 
  are 
  present 
  

   sparingly. 
  The 
  common 
  siliceous 
  shale 
  contains 
  very 
  little 
  lime 
  and 
  

   no 
  Foraminifera 
  have 
  been 
  found 
  in 
  it 
  in 
  this 
  district, 
  although 
  they 
  

   have 
  been 
  reported 
  from 
  the 
  typical 
  Monterey 
  shale 
  elsewhere. 
  

   R. 
  M. 
  Bagg 
  c 
  found 
  66 
  species 
  belonging 
  to 
  17 
  genera 
  hi 
  chocolate- 
  

   colored, 
  soft, 
  fine-grained 
  shale 
  of 
  the 
  same 
  formation 
  near 
  Asuncion, 
  

   San 
  Luis 
  Obispo 
  County. 
  J. 
  C. 
  Branner 
  in 
  the 
  introduction 
  to 
  

   Bagg's 
  paper, 
  describes 
  the 
  shale 
  as 
  follows: 
  "The 
  shale 
  proper 
  also 
  

   varies; 
  at 
  some 
  places 
  it 
  is 
  flinty, 
  at 
  others 
  it 
  is 
  somewhat 
  sandy, 
  

   and 
  at 
  still 
  others 
  it 
  is 
  soft 
  and 
  chocolate-colored, 
  and 
  contains 
  an 
  

   abundance 
  of 
  well-preserved 
  Foraminifera. 
  * 
  * 
  * 
  The 
  bulk 
  of 
  

  

  a 
  Geology 
  of 
  Point 
  Sal: 
  Bull. 
  Dept. 
  Geology, 
  Univ. 
  California, 
  vol. 
  2, 
  No. 
  1, 
  1896, 
  p. 
  9. 
  

  

  &Op. 
  cit., 
  p. 
  10. 
  

  

  c 
  Miocene 
  Foraminifera 
  from 
  the 
  Monterey 
  shale, 
  California: 
  Bull. 
  U. 
  S. 
  Geol. 
  Survey 
  No. 
  268, 
  1905. 
  

  

  