COAL  FIELDS  OF  THE  NORTHEAST  SIDE  OF  THE 
BIGHORN  BASIN,  WYOMING,  AND  OF 
BRIDGER,  MONTANA. 
By  Chester  W.  Washburne. 
INTRODUCTION. 
This  report  describes  the  coal  fields  of  the  northeast  side  of  the 
Bighorn  Basin,  Wyoming,  north  of  No  Wood  Creek,  and  also  includes 
the  connected  Bridger  field  in  southern  Montana.  The  field  work 
was  done  in  the  summer  of  1907,  under  the  general  direction  of  C.  A. 
Fisher.  Max  A.  Pishel,  E.  F.  Schramm,  and  Homer  P.  Little  acted 
as  field  assistants.  The  territory  was  surveyed  both  topographically 
and  geologically,  land-survey  lines  being  the  basis  of  horizontal  con- 
trol. Land  corners  were  located  by  pacing  along  alternate  section 
lines,  but  where  the  geology  or  topography  is  intricate,  or  where  the 
coal  is  valuable,  every  east-west  section  line  was  run.  The  outcrops 
of  the  workable  coal  beds  were  meandered,  and  at  every  available 
point  they  were  measured. 
Previous  reconnaissance  work  on  the  coal  of  this  area  has  been 
done  by  Eldridge,a  Fisher,6  and  Darton.c 
LOCATION  AND   EXTENT. 
The  fields  described  in  this  paper  are  located  mostly  in  the  north- 
eastern part  of  the  Bighorn  Basin,  Wyoming,  but  extend  northwest- 
ward across  the  valley  of  Clark  Fork  to  the  vicinity  of  Joliet,  Mont. 
The  length  of  the  territory  is  102  miles,  the  maximum  width  30 
miles,  and  the  total  area  about  1,700  square  miles.  Bighorn  River 
flows  through  the  southeastern  part. 
TOPOGRAPHY. 
The  Bighorn  Basin  is  essentially  a  region  of  broad,  dissected  plains, 
composed  superficially  of  Tertiary  deposits  and  Recent  wash  from  the 
surrounding  mountains.  The  controlling  factor  in  the  topography 
is  Bighorn  River,  which  enters  the  basin  after  passing  through  the 
Owl  Creek  Mountains  in  a  canyon,  traverses  the  east  side  of  the 
<(  Kldridge,  G.  H.,  A  geological  reconnaissance  in  northwest  Wyoming:  Bull.  U.  S.  Geol.  Survi 
119,  1894. 
b  Fisher,  C.  A.,  Coal  of  the  Bighorn  Basin,  in  northwest  Wyoming:  Bull.  U.  S.  Geol.  Sin 
1904,  pp.  345-302;  Mineral  resources  of  the  Bighorn  Basin,  Wyoming:  Bull.  U.  S.  Geol.  Survey  \ 
1906,  pp.  311-312;  Geology  and  water  resources  of  the  Bighorn  Basin,  WyonMng:  Prof.   Paper  U.  S. 
Geol.  Survey  No.  53,  1900,  pp.  46  56. 
cDarton  N.  H.,  Coals  of  Carbon  County,  Montana:  Bull,  i '.  s.  Geol.  Survej  No.  316,  1907,  pp.  L' 
165 
