32  CONTRIBUTIONS    TO    ECONOMIC    GEOLOGY,   1907,   PART   II. 
The  lower  bench  is  partially  concealed,  but  is  reported  to  be  10 
feet  thick  and  to  be  underlain  by  clay.  This  bed  also  occurs  in  the 
base  of  Rocky  Butte,  in  sec.  34,  but  is  so  concealed  by  clinker  that 
no  measurement  of  its  thickness  could  be  made.  To  judge  from  the 
thickness  of  clinker  produced  by  its  burning  along  the  outcrop,  how- 
ever, it  is  in  all  probability  workable. 
In  the  base  of  Square  Butte,  in  T.  139  N.,  R.  103  W.,  beds  F  and 
G  are  separated  by  25  feet  of  sandy  clay.  Their  outcrops  have  been 
so  completely  burned  that  the  coal  is  exposed  at  only  a  few  points. 
Bed  G,  exposed  in  the  NE.  \  sec.  9,  T.  139  N.,  R.  103  W.,  is  15  feet 
thick  without  partings.  Bed  F  is  about  5  feet  thick.  A  few  small 
isolated  buttes,  underlain  by  these  two  members  of  the  group,  lie 
between  Square  Butte  and  Little  Missouri  River,  but  the  presence 
of  clinker  prevented  any  measurements.  Bed  G  occurs  in  the  base 
of  Camels  Hump  Butte,  in  sees.  9  and  10,  T.  140  N.,  R.  104  W.,  as 
indicated  by  the  fringe  of  clinker  left  by  its  burning,  but  no  actual 
exposure  could  be  seen. 
In  the  southeastern  part  of  T.  141  N.,  R.  102  W.,  bed  F  outcrops 
near  the  top  of  a  plateau,  250  feet  above  the  level  of  Little  Missouri 
River.  It  thins  out  toward  the  north  and  is  worthless.  In  the  N.  J 
sec.  35  only  the  upper  6^  feet  of  the  bed  could  be  seen. 
In  the  northern  part  of  T.  142  N.,  R.  101  W.,  bed  F,  the  lowest 
member  of  the  group,  is  divided  and  replaced  by  partings  so  that 
little  of  it  remains.  Here  the  upper  members  of  the  group  are  thin 
and  dirty. 
In  the  eastern  part  of  T.  142  N.,  R.  102  W.,  and  in  T.  142  N., 
R.  103  W.,  bed  G  outcrops  near  the  top  of  the  higher  divides  in  the 
badlands.  It  is  250  feet  above  the  river  level,  ranges  in  thickness 
from  3  to  5  feet,  and  is  scarcely  accessible  for  mining  operations. 
A  few  isolated  buttes  of  sufficient  height  to  contain  bed  F  are 
found  in  T.  141  N.,  R.  103  W.,  and  in  T.  142  N.,  R,  104  W.,  but  the 
rocks  are  either  barren  or  contain  thin,  unworkable  beds  of  lignite. 
In  T.  141  N.,  R.  101  W.,  bed  F,  at  the  contact  of  the  somber- 
colored  beds  and  the  lighter  beds  below,  occurs  in  more  or  less  iso- 
lated buttes  on  the  divides  between  Franks  Creek  and  Government 
Creek,  at  an  elevation  of  about  250  to  300  feet  above  Little  Missouri 
River.  In  the  SW.  |  sec.  5  a  small  butte  is  underlain  by  this  bed, 
which  is  11  feet  6  inches  thick,  with  a  3-inch  clay  parting  6  inches 
from  the  bottom.  In  the  NW.  I  SE.  I  sec.  12  an  exposure  of  a  part 
of  the  bed  measures  16  feet.  It  is  probably  not  much  thicker.  A 
part  of  the  S.  \  sec.  36  is  underlain  by  this  bed,  but  the  presence  of 
clinker  prevented  any  measurements. 
In  sees.  8,  9,  10,  16,  and  17,  T.  140  N.,  R.  102  W.,  at  an  elevation 
of  about  275  feet  above  Little  Missouri  River,  an  irregular  plateau  is 
underlain  by  bed  F,  the  lowest  member  of  the  group.  Its  outcrop 
is  usually  concealed  by  clinker,  and  no  satisfactory  measurements  of 
its  thickness  could  be  made. 
