﻿150 
  G. 
  H. 
  Stone 
  — 
  Asphaltum 
  of 
  Utah 
  and 
  Colorado. 
  

  

  the 
  limestone 
  is 
  of 
  a 
  light 
  color, 
  this 
  liquid 
  must 
  have 
  acquired 
  

   its 
  dark 
  color 
  during 
  the 
  process 
  of 
  being 
  changed 
  into 
  hard 
  

   asphalt. 
  This 
  conclusion 
  is 
  confirmed 
  by 
  the 
  lighter 
  color 
  of 
  

   the 
  least 
  exposed 
  asphalt. 
  Evidently 
  the 
  bituminous 
  matter 
  

   that 
  is 
  now 
  in 
  the 
  rock 
  is 
  not 
  in 
  the 
  condition 
  of 
  ordinary 
  

   black 
  asphalt, 
  but 
  the 
  liquid 
  which 
  oozed 
  out 
  of 
  the 
  rock 
  was 
  

   capable 
  of 
  being 
  changed 
  into 
  such 
  asphalt, 
  hence 
  the 
  bitumin- 
  

   ous 
  limestones 
  may 
  well 
  be 
  classed 
  with 
  the 
  asphalt-producing 
  

   rocks. 
  

  

  The 
  rather 
  light 
  color 
  of 
  some 
  of 
  these 
  masses 
  of 
  hard 
  

   asphalt, 
  which 
  have 
  all 
  the 
  properties 
  of 
  Uintaite 
  except 
  the 
  

   deep 
  black 
  color, 
  suggests 
  the 
  question 
  whether 
  the 
  color 
  of 
  

   asphalt 
  be 
  not 
  due 
  to 
  disseminated 
  fixed 
  carbon, 
  in 
  a 
  state 
  ap- 
  

   proaching 
  charcoal, 
  the 
  product 
  of 
  partial 
  oxidation, 
  more 
  

   than 
  to 
  the 
  natural 
  color 
  of 
  the 
  hydro-carbons 
  proper. 
  I 
  began 
  

   some 
  experiments 
  and 
  analyses 
  to 
  determine 
  this 
  point, 
  but 
  the 
  

   work 
  is 
  incomplete.* 
  

  

  * 
  4. 
  Outflow 
  or 
  Overflow 
  Asphalt. 
  — 
  Under 
  this 
  class 
  are 
  here 
  

   included 
  all 
  forms 
  of 
  asphalt 
  that 
  have 
  oozed 
  out 
  of 
  the 
  rock 
  

   that 
  originally 
  contained 
  them. 
  Some 
  of 
  these 
  had 
  the 
  black 
  

   color 
  before, 
  others 
  have 
  acquired 
  it 
  since 
  the 
  outflow. 
  I 
  

   leave 
  it 
  as 
  an 
  ojDen 
  question 
  whether 
  these 
  oils 
  were 
  true 
  

   asphalts 
  before 
  acquiring 
  the 
  black 
  color. 
  f 
  

  

  Mineralogically 
  the 
  outflow 
  asphalts 
  present 
  the 
  same 
  diffi- 
  

   culties 
  of 
  classification 
  as 
  do 
  the 
  petroleums. 
  There 
  are 
  per- 
  

   haps 
  a 
  dozen 
  different 
  grades 
  in 
  Utah 
  and 
  Colorado 
  that 
  might 
  

   be 
  described 
  as 
  distinct 
  minerals 
  by 
  those 
  on 
  the 
  alert 
  for 
  new 
  

   species. 
  The 
  more 
  important 
  generic 
  terms 
  (they 
  are 
  all 
  

   generic 
  rather 
  than 
  specific) 
  are 
  the 
  following 
  : 
  1. 
  Maltha, 
  

   asphaltic 
  tar, 
  brea,' 
  mineral 
  tar 
  or 
  pittasphalt. 
  Here 
  are 
  in- 
  

   cluded 
  the 
  viscous 
  liquids. 
  In 
  Utah 
  they 
  all 
  have 
  an 
  aromatic 
  

   odor 
  and 
  black 
  color. 
  By 
  degrees 
  they 
  harden 
  to 
  a 
  solid, 
  

   sometimes 
  tough, 
  waxy 
  or 
  horny, 
  sometimes 
  brittle. 
  The 
  

  

  * 
  Mr. 
  S. 
  H. 
  Gilson, 
  of 
  Salt 
  Lake, 
  informs 
  trie 
  that 
  lie 
  has 
  obtained 
  by 
  distilla- 
  

   tion 
  of 
  the 
  limestone 
  out 
  of 
  which 
  a 
  mass 
  of 
  Wurtzilite 
  had 
  oozed, 
  a 
  dark 
  yellow- 
  

   ish 
  tarry 
  material 
  that 
  closely 
  resembles 
  and 
  appears 
  to 
  be 
  identical 
  with 
  the 
  

   distillate 
  from 
  the 
  Wurtzilite. 
  

  

  f 
  That 
  the 
  lighter 
  constituents 
  of 
  petroleum 
  can 
  be 
  changed 
  to 
  more 
  viscous 
  

   oils 
  by 
  protracted 
  exposure 
  to 
  oxygen, 
  appears 
  to 
  have 
  been 
  proved 
  by 
  experi- 
  

   ments 
  made 
  some 
  years 
  ago 
  by 
  W. 
  P. 
  Jenney. 
  The 
  same 
  conclusion 
  is 
  enforced 
  

   by 
  the 
  hardening 
  of 
  the 
  brea 
  of 
  California, 
  also 
  by 
  the 
  finding 
  of 
  asphalt 
  in 
  cavi- 
  

   ties 
  in 
  the 
  Devonian 
  and 
  Silurian 
  petroliferous 
  rocks 
  (see 
  Report 
  of 
  Professor 
  

   Edward 
  Orton 
  on 
  the 
  Trenton 
  Limestone 
  as 
  a 
  source 
  of 
  Natural 
  Gas 
  and 
  Petro- 
  

   leum 
  in 
  Ohio 
  and 
  Indiana. 
  Eighth 
  Ann. 
  Report 
  Director 
  U. 
  S. 
  G-. 
  S., 
  86-S7). 
  

   Such 
  asphalt 
  cavities 
  have 
  been 
  observed 
  by 
  Shaler, 
  Newberry, 
  Linney, 
  Orton 
  

   and 
  others. 
  In 
  the 
  present 
  state 
  of 
  the 
  argument 
  it 
  is 
  permissible 
  to 
  assume 
  as 
  a 
  

   working 
  hypothesis 
  that 
  the 
  harder 
  asphalts 
  were 
  derived 
  from 
  the 
  softer 
  or 
  

   pittasphalts, 
  and 
  they 
  in 
  turn 
  from 
  more 
  liquid 
  bitumens, 
  under 
  exposure 
  to 
  the 
  

   air 
  or 
  perhaps 
  to 
  aerated 
  waters. 
  How 
  much 
  this 
  is 
  quantitatively 
  due 
  to 
  oxygen 
  

   or 
  other 
  chemica'l 
  agencies, 
  and 
  how 
  much 
  to 
  evaporation 
  of 
  the 
  lighter 
  com- 
  

   pounds, 
  remains 
  to 
  be 
  determined 
  

  

  