﻿224: 
  Taff— 
  Alhertite-lilce 
  Asphalt 
  in 
  the 
  Choctavj 
  Nation. 
  

  

  end 
  of 
  this 
  valley, 
  in 
  Section 
  10, 
  T. 
  1 
  S., 
  R. 
  15 
  E. 
  is 
  anticlinal 
  

   and 
  the 
  rocks 
  along 
  the 
  east 
  side 
  of 
  the 
  valley 
  dip 
  normally 
  

   toward 
  the 
  east. 
  On 
  the 
  west 
  side, 
  however, 
  the 
  older 
  shales 
  

   which 
  contain 
  the 
  albertite 
  are 
  thrust 
  upward 
  against 
  the 
  

   younger 
  sandstones 
  of 
  the 
  hills. 
  

  

  The 
  geology, 
  were 
  it 
  not 
  for 
  the 
  complications 
  of 
  structure, 
  

   would 
  be 
  simple. 
  For 
  all 
  purposes 
  necessary 
  here, 
  however, 
  

   the 
  problem 
  of 
  the 
  geology 
  may 
  be 
  briefly 
  stated. 
  The 
  shales 
  

   which 
  lie 
  in 
  the 
  plains 
  and 
  wide 
  valleys 
  noted 
  above, 
  and 
  which 
  

   contain 
  the 
  albertite, 
  are 
  the 
  oldest 
  known 
  in 
  this 
  district. 
  

   Their 
  thickness 
  is 
  difficult 
  to 
  determine, 
  though 
  it 
  is 
  estimated 
  

   to 
  be 
  several 
  thousand 
  feet. 
  They 
  are 
  composed 
  of 
  greenish 
  

   and 
  bluish 
  clay 
  shales, 
  sandy 
  shale 
  and 
  greenish 
  friable 
  sand- 
  

   stone. 
  Thin 
  beds 
  of 
  black 
  siliceous 
  slate 
  have 
  been 
  noted 
  in 
  

   the 
  upper 
  part 
  of 
  this 
  body 
  of 
  shale. 
  

  

  All 
  the 
  thick 
  sandstones 
  which 
  form 
  the 
  hills 
  and 
  ridges 
  lie 
  

   above 
  the 
  shales. 
  The 
  aggregate 
  thickness 
  of 
  these 
  sandstones 
  

   is 
  estimated 
  also 
  to 
  be 
  several 
  thousand 
  feet. 
  Beds 
  of 
  lime- 
  

   stone 
  which 
  have 
  been 
  found 
  to 
  occur 
  just 
  above 
  the 
  sandstone 
  

   formation 
  contain 
  fossils 
  of 
  Ordovician 
  age. 
  Hence 
  it 
  is 
  con- 
  

   cluded 
  that 
  the 
  sandstones 
  and 
  the 
  shales 
  which 
  contain 
  the 
  

   albertite 
  are 
  of 
  Ordovician 
  age 
  or 
  older. 
  

  

  Conclusions. 
  

  

  The 
  mineral, 
  in 
  both 
  its 
  physical 
  and 
  chemical 
  properties, 
  is 
  

   shown 
  to 
  be 
  an 
  asphalt 
  and 
  more 
  closely 
  related 
  to 
  albertite 
  

   than 
  to 
  any 
  other 
  known 
  asphalt 
  substance. 
  Indeed 
  its 
  only 
  

   variation 
  from 
  albertite 
  of 
  any 
  moment 
  is 
  its 
  solubility 
  in 
  tur- 
  

   pentine. 
  The 
  friability 
  and 
  fracture 
  of 
  the 
  sample 
  submitted 
  

   for 
  analysis 
  is, 
  without 
  much 
  doubt, 
  due 
  to 
  its 
  structural 
  con- 
  

   dition 
  produced 
  by 
  pressure 
  after 
  solidification. 
  The 
  product 
  

   occurs 
  as 
  veins 
  or 
  dikes 
  filling 
  fissures 
  along 
  zones 
  of 
  thrust 
  

   faulting. 
  It 
  occurs 
  in 
  shales 
  of, 
  at 
  present, 
  unknown 
  age. 
  

  

  The 
  quantity 
  of 
  this 
  asphalt 
  can 
  be 
  conjectured 
  only. 
  

   As 
  far 
  as 
  known 
  it 
  occurs 
  in 
  thin 
  stringers, 
  in 
  a 
  vein 
  about 
  

   4 
  feet 
  thick, 
  and 
  in 
  a 
  vein 
  about 
  25 
  feet 
  thick. 
  The 
  

   surface 
  of 
  the 
  shale 
  containing 
  the 
  product 
  is 
  worn 
  down 
  in 
  

   valleys 
  and 
  concealed 
  by 
  soil 
  or 
  overwash 
  so 
  that 
  the 
  asphalt 
  

   is 
  known 
  only 
  so 
  far 
  as 
  prospected. 
  From 
  the 
  manner 
  of 
  its 
  

   occurrence 
  in 
  fissures 
  produced 
  by 
  fracture, 
  where 
  it 
  has 
  suffered 
  

   probably 
  great 
  pressure, 
  the 
  vein 
  is 
  supposed 
  to 
  vary 
  in 
  thick- 
  

   ness 
  and 
  in 
  longitudinal 
  extent 
  and 
  may 
  descend 
  to 
  any 
  reason- 
  

   able 
  depth. 
  

  

  