SENTINEL   BUTTE   LIGNITE   FIELD,   N.   DAK.    AND   MONT. 
Section  near  mouth  of  Knutson  Creek,  in  the  NW.  %  sec.  11,  T.  140  N.,  R.  102  W. 
Ft.     in. 
Bed  D:  Lignite 5    6 
Clay,  sandy 25 
Bed  C:  Lignite 9 
Concealed  to  river  level 20 
Total  lignite 14    6 
A  bed  of  lignite  5  feet  thick  exposed  in  the  south  bank  of  Little 
Missouri  River,  in  the  NE.  \  sec.  32,  T.  141  N.,  R.  101  W.,  probably 
represents  the  second  member  below  the  top  of  the  Medora  group, 
the  other  members  being  present  below  the  level  of  the  river. 
Bed  E  shows  workable  thickness,  and  its  outcrop  has  been  mapped 
along  the  banks  of  Andrews  Creek,  in  T.  140  N.,  R.  104  W.7  near  the 
town  of  Sentinel  Butte.     Two  sections  follow: 
Section  of  bed  E  in  the  NE.  \  SW.  \  sec.  21,  T.  140  N,  R.  104  W. 
Ft.     in. 
Sandstone,  soft,  yellowish 20 
Lignite 5    2 
Clay 5    6 
Lignite 1 
Clay 5    6 
Lignite 1    6 
Total  lignite 7     8 
Section  of  bed  E  in  the  SE.  \  sec.  22,  T.  140  N.,  R.  104  W. 
Ft.    in. 
Clay,  blue,  sandy 6 
Lignite 1     6 
Clay,  bituminous 4 
Lignite 5 
Total  lignite \ '  6    6 
An  exposure  of  bed  C  in  sec.  11,  T.  142  N.,  R.  102  W.,  on  the  east 
side  of  Little  Missouri  River,  shows  the  following  section: 
Section  of  bed  C  in  east  bank  of  Little  Missouri  River,  in  sec.  11,  T.  142  N.,  R.  102  W. 
Clay,  sandy.  Ft.    in. 
Lignite 1 
Clay 5      G 
Lignite 3 
Clay,  sandy 6 
Lignite 6 
Clay,  sandy 3      6 
Lignite 6 
Clay. 
Total  lignite 1G 
