LEWISTOWN    COAL   FIELD,   MONTANA.  115 
ranches  and  to  the  settlements  in  the  vicinity  of  Judith  Gap.     There 
is  an  abandoned  mine  on  Buffalo  Creek,  owned  by  J.  A.  Dover. 
ROCK    CREEK   DISTRICT. 
General  conditions. — The  Rock  Creek  district  is  located  in  T.  13  N., 
R.  17  E.  The  coal  outcrop  on  the  north  side  of  Rock  Creek  in  its 
east-west  course  through  sees.  15  and  16  marks  the  southern  limit  of 
the  district.  Thinning  of  the  coal  limits  the  district  in  other  direc- 
tions, and  the  area  of  workable  coal  includes  less  than  3  square  miles. 
There  is  apparently  but  one  coal  bed  in  this  district.  It  occurs  in 
two  benches,  separated  by  a  parting  of  dark  bone.  In  some  places 
the  coal  is  overlain  by  bone;  in  others  sandstone  rests  upon  the  upper 
bench.  A  representative  section  of  the  coal  bed  in  this  district  is 
given  below. 
Representative  section  of  coal  bed  in  Rock  Creek  district. 
Sandstone.  Ft.  in. 
Bone 10 
( !oal : 1 
Bone 1  I 
Coal 2  2 
5      1 
Carboniferous  coal. — The  only  locality  in  the  Lewistown  field  where 
coal  was  noted  below  the  Cretaceous  is  in  the  vicinity  of  Rock  Creek. 
Here  a  prospect  in  the  NW.  J  sec.  23  has  discovered  a  6-inch  bed  in 
the  Quadrant  formation,  of  Pennsylvanian  (?)  age.  It  is  improbable 
that  workable  coal  will  be  found  at  this  horizon  anywhere  in  the  field, 
although  its  presence  has  led  to  some  prospecting  in  the  district 
between  the  Big  Snowy  Mountains  and  the  mines  on  Rock  Creek. 
Development. — There  are  four  mines  in  the  Rock  Creek  district. 
Three  of  these — the  Sharp,  Cooper,  and  Rand  mines — are  along  Rock 
Creek,  and  the  fourth,  the  Knox  mine,  is  on  the  west  fork  of  Beaver 
Creek  in  sec.  3.  All  are  small  producers,  supplying  fuel  to  ranchers 
near  by  and  also  to  the  town  of  Moore. 
WARM    SPRING    CREEK    DISTRICT. 
General  conditions. — The  Warm  Spring  Creek  district  comprises 
the  northern  part  of  T.  16  N.  and  the  southern  part  of  T.  17  N., 
R.  19  E.  In  a  measure  the  limits  of  the  district  are  ill  defined, 
except  where  the  coal  outcrops  in  the  embayment  on  the  north- 
western side  of  the  Judith  Mountains.  To  the  north  the  district 
extends  across  Warm  Spring  Creek,  but  the  coal  thins  in  that  direc- 
tion, as  shown  by  exposures  in  several  small  laccolithic  uplifts  aorth 
of  the  creek.     To  the  northwest  the  coal-bearing  rocks  are  overlain 
