COAL   OF   BRIDGER   FIELD,    MONTANA.  189 
About  1  mile  farther  north,  in  sec.  9,  T.  7  S.,  R.  23  E.,  about  3f 
miles  south  of  Bridger,  the  following  section  was  obtained  in  an  old 
prospect: 
Section  of  coal  bed  in  a  prospect  31  miles  south  of  Bridger,  in  si  c.  9,  '/'.  7  S.,  R.  23  E. 
Ft.  in. 
Shale,  sandy 2 
Coal 5 
Clay 8 
Coal 2  6 
Total  coal 2      !l 
North  of  this  point  the  outcrop  of  the  coal  bed  disappears  beneath 
the  alluvium  of  the  Clark  Fork  valley.  It  reappears  in  the  hills  on 
the  northwest  side  of  the  valley  and  runs  along  the  cliffs  northward 
across  T.  6  S.,  R.  23  E.  In  the  NE.  \  sec.  29  the  following  sect  ion  was 
made : 
Section  of  coal  bed  1  mile  southwest  of  Bridger,  in  sec.  29,  T.  6  S.,  R.  23  E. 
Ft.    in. 
Sandstone,  thin-bedded,  yellow 5 
Sandstone,  thin-bedded,  and  shale,    carbonaceous,    with    coaly 
streaks 1     3 
Coal 1    9 
Shale l\ 
Coal 8 
Total  coal 2     5 
At  the  mine  of  the  Bridger  Coal  Improvement  Company,  in  the 
SW.  i  sec.  17,  T.  6  S.,  R.  23  E.,  1  mile  northwest  of  Bridger,  the  follow- 
ing section  was  measured : 
Section  of  coal  in  Bridger  mine. 
Ft.       in. 
( !oal 1        2 
Shale 6   is 
Coal 3        6 
Shale  and  sandstone    1 
Shale • 6 
( !<  >al I 
Total  coal 5        8 
Sandstone,  with  a  Little  shale 20 
Coal  ( reported  as  good  blacksmith  coal ) I        9 
Clay,  white,  soft 
This  mine  was  opened  in  1897  and  commenced  shipping  coal  in  1898. 
It  is  worked  by  the  long-wall  method.  A  mining  machine  is  used  in 
driving  air  courses  and  gangways.  In  the  deeper  parts  of  the  present 
workings,  where  the  coal  is  about  800  feet  deep,  the  roof  pressure  is 
