THE  LEWISTOWN  COAL  FIELD,  MONTANA. 
By  W.  R.  Calvert. 
INTRODUCTION. 
The  present  paper,  which  is  to  be  considered  as  a  preliminary 
statement/'  sets  forth  briefly  the  results  of  a  detailed  survey  of  the 
Lewistown  coal  field  made  in  the  summer  of  1907  by  Eugene  Steb- 
inger,  J.  B.  Umpleby,  and  the  writer,  under  the  general  supervision 
of  C.  A.  Fisher.  As  the  primary  object  of  the  investigation  was  the 
classification  of  the  public  lands  with  respect  to  coal,  the  work  was 
conducted  with  a  view  of  ascertaining  the  extent  of  coal  areas  and 
their  relation  to  legal  land  subdivisions.  In  the  central  and  west- 
ern parts  of  the  field  railroad  profiles  gave  excellent  vertical  control; 
in  the  northeastern  part  the  Geological  Survey  has  run  several  lines 
of  level  and  determined  many  elevations.  The  accompanying  map 
(PL  VII)  is  introduced  chiefly  to  show  the  relation  of  the  coal  out- 
crop and  coal  areas  to  land  subdivisions.  The  detailed  information 
acquired  in  the  course  of  the  work,  concerning  the  geology  and 
coal  resources  of  the  region,  will  appear  in  the  final  report. 
The  Lewistown  coal  field  has  not  been  examined  in  detail  by  pre- 
vious workers.  In  1879  Eldridge6  traced  the  coal  outcrop  westward 
from  Judith  River  to  Belt  Creek,  but  only  brief  mention  of  the  coals 
of  the  Lewistown  field  is  made  in  his  report.  Weed  and  Pirsson,c 
in  their  report  on  the  Judith  Mountains,  discuss  at  some  length  the 
coal  in  the  vicinity  of  that  uplift.  Various  other  geologists  also 
have  made  brief  reference  to  this  coal  field. 
LOCATION  AND   EXTENT. 
The  Lewistown  coal  field,  as  herein  described,  comprises  not  only 
the  limited  district  near  Lewistown,  where  considerable  develop- 
ment has  taken  place,  but  also  the  western  extension  of  that  dis- 
trict, connecting  with  work  done  the  previous  year  in  the  Great 
<*  A  full  report  on  this  coal  field  is  now  in  course  of  preparation,  and  will  appear  as  a  separate  publi- 
cation of  the  Geological  Survey. 
b  Eldridge,  G.  H.,  Montana  coal  fields:  Tenth  Census,  vol.  15, 1886,  pp.  740-757. 
o  Weed,  W.  H.,  and  Pirsson,  L.  V.,  Geological  and  mineral  resources  of  the  Judith  Mountains,  Mon- 
tana; Eighteenth  Ann  Rept.  U.  S.  Geol.  Survey,  pt.  3,  1898,  pp.  443-621. 
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