DEVELOPMENT  OF  THE  BEAR  CREEK  COAL  FIELDS, 
MONTANA. 
By  Cassius  A.  Fisher. 
i  Introduction. — During  the  field  season  of  1903  a  preliminary  examination  was  made  of 
the  coal  deposits  of  the  Bighorn  basin  in  northwestern  Wyoming.  At  the  close  of  this 
investigation,  for  the  purpose  of  comparison,  the  writer  made  a  brief  examination  of  the 
Bear  Creek  and  Red  Lodge  coal  fields,  which  lie  next  north,  in  the  southern  part  of  Montana. 
Coal  has  been  mined  extensively  at  Red  Lodge,  Mont.,  for  a  number  of  years,  but  it  is 
only  recently  that  attention  has  been  directed  to  the  extensive  development  of  the  Bear 
Creek  deposits.  In  view  of  this  proposed  development  the  Bear  Creek  deposits  were 
revisited  at  the  close  of  the  last  field  season  and  additional  data  obtained  regarding  the 
character,  thickness,  and  stratigraphic  position  of  the  coal  beds  and  the  present  plans  for 
development. 
Previous  work. — The  first  investigations  in  this  field  were  conducted  by  Mr.  J.  E.  Wolff, 
of  the  Northern  Transcontinental  Survey,  a  W.  H.  Weed,  of  the  United  States  Geological 
Survey, &  has  since  described  these  beds,  in  connection  with  other  coal  deposits  in  Montana, 
and  a  brief  statement  of  the  nature  of  the  deposits  was  published  by  the  late  G.  H.  Eldridge.c 
Location  and  extent. — The  Bear  Creek  coal  district  occupies  the  highland  lying  at  the 
base  of  the  Bear  Tooth  Mountains  in  the  southwestern  part  of  Carbon  County,  Mont., 
near  the  headwaters  of  Rocky  Fork,  a  small  tributary  of  Yellowstone  River.  The  area 
underlain  by  coal  is  about  3  miles  wide  and  extends  in  a  northwest-southeast  direction, 
the  limits  of  which  have  been  only  indefinitely  determined.  On  the  south  these  coal- 
bearing  beds  probably  do  not  extend  to  the  Wyoming  State  line,  and  to  the  west  of  Red 
Lodge  they  are  covered  by  a  considerable  thickness  of  a  more  recent  formation. 
Stratigraphy. — The  coal  of  the  Bear  Creek  district  occurs  in  the  upper  part  of  the  so-called 
Laramie  formation,  which  here  consists  of  a  series  of  alternations  of  sandstone,  shale,  and 
clay  of  variable  thickness.  The  shales  are  dark  gray  and  usually  very  sandy.  The  sand- 
stones are  lighter  gray  and  often  iron  stained.  They  occur  in  beds  25  to  30  feet  thick  and 
are  generally  sufficiently  soft  to  weather  uniformly  with  the  intercalated  shales. 
Coal. — The  coal  occurs  within  a  series  of  beds  less  than  600  feet  thick  and  in  this  mass 
there  are  at  least  seven  workable  coal  beds.  They  vary  in  thickness  from  4  to  10^  feet 
and  comprise  a  total  of  i  ppioximately  45  feet.  These  different  coal  beds  are  designated 
as  Nos.  1  to  7,  beginning  at  the  top.  No.  1  has  a  thickness  of  6  feet,  with  a  few  thin 
partings  near  the  middle.  No.  2  is  65  feet  thick  and  is  overlain  by  a  dark  shale  of  variable 
thickness.  No.  3  has  a  total  thickness  of  10^  feet,  with  a  parting  of  varying  width  near 
the  middle.  The  roof  is  hard,  rendering  it  unnecessary  to  timber  the  rooms  and  entries.  No. 
4  is  4|  feet  thick  and  contains  a  few  small  partings.  No.  5  has  a  thickness  of  4§  feet, 
with  one  small  parting  of  bony  coal.  The  roof  of  No.  5  is  composed  of  massive  gray  sand- 
stone; the  floor  of  a  gray,  compact  clay.     No.  6  has  a  total  thickness  of  about  A\  feet, 
a  Wolff,  J.  E.,  Report  on  the  Rock  Creek  coal  field,  Montana:  Tenth  Census  of  the  United  States,  1886 
pp.  755  and  plates. 
b  Weed,  W.  H.,  The  coal  fields  of  Montana:  Eng.  and  Min.  Jour.,  vol.  53,  No.  20,  1892, pp.  520-522. 
c  Eldridge,  G.  H.,  A  geological  reconnaissance  in  northwest  Wyoming:  Bull.  U.  S.  Geol.  Survey  No 
119,  1894,  p.  53. 
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