310         CONTRIBUTIONS    TO    ECONOMIC   GEOLOGY,   1907,    PART   II. 
HENRYS  FORK  FIELD. 
GENERAL    STATEMENT. 
Coal  has  been  reported  from  the  vicinity  of  Henrys  Fork  in  north- 
eastern Utah  and  southern  Wyoming,  although  very  little  precise 
information  concerning  this  field  has  heretofore  been  available. 
About  ten  days  at  the  close  of  the  season  were  spent  in  the  field, 
reviewing  the  geology  and  looking  up  some  of  the  known  occurrences 
of  coal. 
LOCATION. 
The  name,  Henrys  Fork  coal  field,  has  been  applied  in  a  rather 
indefinite  way  to  reported  coal  croppings  in  the  vicinity  of  the  valley 
of  Henrys  Fork,  near  the  junction  of  that  stream  with  Green  River. 
This  district  lies  along  the  State  line  in  northeastern  Uinta  County, 
Utah,  and  southern  Uinta  County,  Wyo.  It  is  40  to  60  miles  from 
the  Union  Pacific  Railroad  either  at  Green  River  or  at  Carter,  Wyo., 
the  customary  mail  route  going  to  the  latter  point. 
STRUCTURE. 
The  field  lies  north  of  the  Uinta  Mountains  and  is  structurally  a 
part  of  the  Green  River  Basin,  or  of  the  Bridger  Basin  if  the  larger 
structural  feature  be  considered  as  divided  by  the  Rock  Springs 
dome.  In  general  the  strata  in  this  field  are  tilted  to  the  north  away 
from  the  axes  of  the  Uinta  Range.  These  mountains  separate  the 
Henrys  Fork  field  from  the  Vernal  field,  just  described.  Structurally 
the  Henrys  Fork  field  is  directly  related  to  the  Yampa  field,  with 
which  its  rocks  are  doubtless  connected  or  continuous,  except  where 
they  are  eroded  and  covered  by  the  overlap  of  the  Tertiary  rocks  or 
are  cut  out  by  faulting.  The  northern  flank  of  the  Uinta  Range  is 
much  broken  by  faults  and  as  some  of  these  are  largely  obscured 
by  the  Tertiary  strata  that  unconformably  overlie  the  older  rocks, 
the  geology  of  a  part  of  the  field  is  not  very  clearly  revealed. 
STRATIGRAPHY. 
The  Cretaceous  formations  correspond  to  those  of  the  Yampa 
field.  Where  not  faulted  out  the  Mesaverde  formation  is  coal  bear- 
ing. The  relations  of  the  Lewis  shale  to  the  overlying  Wasatch 
strata  are  obscure,  but  it  seems  certain  that  either  displacement 
by  faulting  or  erosional  unconformity  has  obscured  the  Laramie,  at 
least  near  Green  River,  where  those  beds  might  be  expected,  on  the 
east  side  of  the  valley  above  Flaming  Gorge. 
