﻿154 
  G. 
  H. 
  Stone 
  — 
  Asphaitum 
  of 
  Utah 
  and 
  Colorado. 
  

  

  They 
  are 
  distributed 
  through 
  several 
  hundred 
  feet 
  of 
  shales 
  

   (or 
  marls) 
  and 
  occasional 
  limestones. 
  Each 
  stratum 
  bears 
  its 
  

   own 
  proportion 
  of 
  bitumen 
  over 
  large 
  areas. 
  The 
  richer 
  strata 
  

   are 
  not 
  those 
  nearest 
  the 
  limestones 
  and 
  they 
  alternate 
  with 
  

   low 
  grade 
  strata. 
  There 
  are 
  no 
  veins 
  or 
  highly 
  bituminized 
  

   tracts 
  leading 
  from 
  the 
  limestones 
  out 
  into 
  the 
  shales, 
  nor 
  any 
  

   other 
  field 
  evidence 
  that 
  after 
  deposition 
  the 
  shales 
  were 
  

   bituminized 
  from 
  the 
  limestones. 
  Indeed 
  these 
  black 
  shales 
  

   are 
  a 
  very 
  impenetrable 
  rock. 
  When 
  veins 
  of 
  asphalt 
  cross 
  

   both 
  limestones 
  and 
  shales 
  the 
  asphalt 
  has 
  in 
  no 
  place 
  that 
  I 
  

   have 
  discovered 
  passed 
  out 
  into 
  the 
  shales 
  and 
  super-charged 
  

   them. 
  

  

  Certain 
  of 
  the 
  shale 
  strata 
  contain 
  great 
  numbers 
  of 
  imprints 
  

   of 
  deciduous 
  leaves, 
  water 
  plants 
  and 
  insects, 
  larvse, 
  etc. 
  The 
  

   carbonaceous 
  matter 
  of 
  the 
  leaves 
  is 
  not 
  in 
  the 
  form 
  of 
  asphalt, 
  

   but 
  of 
  charcoal 
  or 
  free- 
  burning 
  coal 
  and 
  contains 
  quite 
  a 
  large 
  

   proportion 
  of 
  fixed 
  carbon. 
  It 
  is 
  thus 
  proved 
  that 
  certain 
  

   strata 
  contained 
  a 
  large 
  amount 
  of 
  organic 
  matter. 
  As 
  above 
  

   noted 
  there 
  are 
  occasional 
  thin 
  coal 
  beds 
  in 
  the 
  midst 
  of 
  the 
  

   bituminous 
  shales, 
  but 
  they 
  do 
  not 
  contain 
  more 
  than 
  the 
  

   average 
  quantity 
  of 
  bitumen 
  found 
  in 
  the 
  coals 
  of 
  the 
  period. 
  

   Evidently 
  the 
  conditions 
  for 
  the 
  production 
  of 
  coal 
  are 
  very 
  

   different 
  from 
  those 
  that 
  produce 
  oil 
  and 
  asphalt, 
  but 
  the 
  sur- 
  

   prising 
  thing 
  is 
  that 
  we 
  do 
  not 
  find 
  the 
  two 
  conditions 
  passing 
  

   into 
  one 
  another 
  by 
  transitionary 
  steps. 
  

  

  Thus 
  there 
  is 
  no 
  proof 
  that 
  the 
  shales 
  were 
  bituminized 
  from 
  

   the 
  limestones 
  and 
  the 
  coals 
  have 
  only 
  their 
  indigenous 
  bitumen 
  

   and 
  volatile 
  carbonaceous 
  matter. 
  So 
  far 
  as 
  I 
  have 
  observed, 
  

   the 
  richer 
  bituminous 
  shales 
  and 
  asphaltic 
  sand 
  rocks 
  are 
  mostly 
  

   non-fossiliferous 
  and 
  there 
  is 
  no 
  direct 
  evidence 
  of 
  the 
  former 
  

   presence 
  within 
  them 
  of 
  undecomposed 
  organic 
  matter, 
  except 
  

   a 
  few 
  shells 
  in 
  the 
  sandstones, 
  and 
  some 
  silicified 
  and 
  ferrugi- 
  

   nized 
  wood. 
  

  

  4. 
  If, 
  according 
  to 
  the 
  views 
  of 
  Dr. 
  Newberry, 
  the 
  asphalt 
  

   of 
  the 
  Utah 
  Tertiary 
  beds 
  was 
  derived 
  from 
  the 
  Cretaceous 
  

   black 
  shales, 
  then 
  it 
  must 
  have 
  passed 
  upward 
  either 
  as 
  a 
  liquid 
  

   or 
  as 
  a 
  gas. 
  

  

  1. 
  Did 
  the 
  asphalt 
  originate 
  in 
  a 
  liquid 
  that 
  passed 
  from 
  the 
  

   black 
  shales 
  upward 
  ? 
  It 
  is 
  admitted 
  that 
  the 
  black 
  shales 
  con- 
  

   tain 
  more 
  or 
  less 
  petroleum, 
  though 
  in 
  general 
  these 
  shales 
  

   afford 
  only 
  thin 
  films 
  of 
  oil. 
  This 
  may, 
  however, 
  be 
  due 
  to 
  

   the 
  petroleum 
  having 
  drained 
  off 
  to 
  lower 
  levels 
  during 
  the 
  

   upheavals 
  incident 
  to 
  the 
  elevation 
  of 
  the 
  mountains. 
  From 
  

   the 
  top 
  of 
  the 
  Fox 
  Hills 
  rocks 
  to 
  the 
  lowest 
  of 
  the 
  Tertiary 
  

   asphalt 
  beds 
  there 
  intervene 
  3000 
  feet 
  or 
  more 
  of 
  Laramie 
  and 
  

   Wasatch 
  rocks, 
  mostly 
  sandstone, 
  with 
  thick 
  strata 
  of 
  shales, 
  

   marls 
  and 
  limestones, 
  also 
  several 
  coal 
  beds, 
  and 
  a 
  very 
  impene- 
  

   trable 
  iron-cemented 
  sandrock. 
  If 
  a 
  liquid 
  passed 
  up 
  through 
  

  

  