342  CONTRIBUTIONS    TO    ECONOMIC    GEOLOGY,   1.905. 
The  Evanston  coals  belong  to  Group  I,  which  includes  the  great  majority  of  Iowa,  Illinoi; 
Missouri,  and  Indiana  coals,  and  some  bituminous  coals  from  Wyoming  and  Montana. 
The  Adavi He-Twin  Creek  coals  «  fall  in  Group  d  with  the  Gallup  (X.  Mex.)  and  Bouldc  ! 
(Colo.)  black  lignites. 
Slosson  has  already  shown  that    from   the  standpoint    of    carbon  content   and    calorifi 
value  the  Benton  coals  of   this  region  are  the  best  coals  in  Wyoming.     According   to  th  I 
analyses  made  at  the  United  States  Geological  Survey  coal-testing  plant  of  samples  collect©  i! 
by  Fenneman  and  (rale  in  the  Koutt  County  (Colo.)  field  and  by  J.  A.  Tall'  in  the  Coalvill  \ 
and  Cast  le  Gate  Held  in  Utah,  given  elsewhere  in  this  volume,  the  coals  found  in  this  regie-]  \ 
in  tli*-  Benton  are  better  than  the  best   bituminous  coals  in  t  hese  Colorado  and  Utah  fields 
but  higher  carbon  and  fuel  values  are  shown  in  the  latter  fields  in  portions  of  the  bed  ■] 
which  have  been  altered  to  "anthracite" or  "natural  coke"  by  dikes  or  flows.     Similarly.! 
the  analyses  made  of  the  samples  collected  by  Schrader  and  Shaler  in  the  ( iallup  (N.  Mex. 
field  show  that  on  the  whole  the  Benton  coals  of  Wyoming  are  of  the  same  grade  as  tht  j 
best  coals  of  that   region.     They  are  much  better  than  the  lied  Lodge  (Mont.)  coals  test 
at  St.  Louis. b     On  the  whole,  the  Benton  coals  of  the  Uinta  County  region  may  be  sj: 
to  belong  Dear  the  top  of  the  group  containing  the  best   bituminous  coals  of  the  Kockj 
Mountain  region. 
OIL. 
Oil  has  been  found  in  southern  Uinta  County  in  springs  on  I  lilliard  Fhit  (sec.  4,  T.  13  N. 
R.  L19W.,andsec.33,T.  1  I  X..  \i.  L19W.);  at  Aspen  tunnel  (sec.  12, T.  14  N.,  R.  119  VI 
and  see.  7.  T.  1  I  V.  R.  L18  W.);  3  miles  mat  h  of  Aspen  t  untie],  at  Carter  oil  springs  (sec 
31,  T.  15  X..  R.  1  is  W.);  in  springs  and  wells  on  th,' south  branch  of  Twin  Creek  (T.  21  N. 
R.  117  W.),and  in  wells  near  Spring  Valley  (Tps.  I  I  and  15  X..  R.  lis  \\\). 
HISTOR1     OP    DEVELOPMENT. 
The  .il  spring  near  I  lilliard.  in  the  WW  \  sec.  4,  T.  13  N.,  R.  119  W.,  was  doubtless  wJ 
known  to  the  trappers  who  first  built  the  trading  post  of  Fori  Bridger,  but  the  first  pub- 
lished account  was  the  result  of  an  examination  made  by  the  Mormons  in  their  pioneer 
journey  to  Great   Salt    Lake  in   L847.     W.  Clayton/'  who  accompanied  this  expedition. 
published  in  1^  18  ;i  hi  I  le  book,  which  was  known  lor  years  as  t  he  "  Mormons'  ( itlide  Bookl 
containing  the  following  account  : 
Aboul  a  mile  from  this  place  [the  crossing  of  the  road  over  Sulphur  Creek]  in  a  southwest  course ■ 
a  "  Tar"  or  "Oil"  Spring,  covering  a  surface  of  several  rods  <>f  ground.  A  wagon  trail  runs  within  a 
short  distanc  ..fit.  It  issituated  in  a  small  hollow,  on  the  left  of  the  wagon  trail,  at  a  point  whore 
tii-  i  rail  rises  to  a  higher  bench  of  land.  When  th.'  ..il  can  be  obtaim  <l  free  from  sand,  it  is  useful  to 
oil  wagons.  It  gives  a  nici  polish  to gunstocks,  and  1ms  been  proved  to  be  highly  beneficial  when 
applied  t<>  son's  on  horses,  cal  tie,  etc. 
This  spring  is  mentioned  in  the  accounts  of  Stansburyd  and  Engelmann,<s  but  their 
statements  do  not  differ  materially  from  the  earlier  account  of  Claytonj  It  is  reported 
that  Brigham  Young  caused  a  shallow  well  to  be  dug  at  tin-  point,  and  the  locality  is  now 
known  ;is  the  Brigham  Young  (,il  well  or  spring.     The  oil  was  skimmed  oil"  the  surface  of 
culated  on  the  excessive  air-drying  loss  reported  in  the  Adaville  analyses,  the  Adaville  coal 
belongs  high  in  Group  I,  while  the  Lazeart  coal  belongs  in  Group  J.  According  to  physical  charactejB 
and  general  fuel  value,  these  two  coals  clearly  belong  together  and  are  to  be  regarded  as  high-grade 
black  lignites.  An  examination  of  the  two  original  analyses  will  suffice  to  show  that,  the  air-drying 
losses  reported  for  these  t  wo  coals  are  not  entirely  comparable.    New  analyses  are  now  being  made. 
b  Hull.  I   .  S.  Geol.  Survey  No.  261,  1905,  p.  49. 
c  Clayton,  \\'.,  Th"  Latter-Day  Saints'  Emigrants' Guide:  being  a  Table  of  Distances,  showing  all 
the  springs,  creeks,  rivers,  hills,  mountains,  camping  places,  and  all  other  notable  places,  from  Council 
Bluffs,  to  the  Vallcj  of  the  Greal  .-alt  Lake.  etc.    St.  Louis,  1848,  pp.  18,  21. 
d  Stansbury,  Capt.  Howard,  Exploration  and  Survej  of  the  Valley  of  the  Great  Salt  Lake  of  Utah, 
L852,  p.  280. 
igelmann,  IL,  Preliminary  Report  on  the  Geology  of  the  country  between  Fort  Bridger  and 
Camp  Floyd,  Utah  Territory,  accompanying  Simpson's  Report  on  Wagon  Routes  in  Utah  Territory, 
35th  Cong.,  2d  sess.,  Senate  Ex.  Do,-.,  vol.  10,  No.  .id,  1859,  p.  52. 
