56  CONTRIBUTIONS   TO   ECONOMIC    GEOLOGY,   1907,   PART   II. 
DOMINY    LIGNITE    GROUP. 
The  most  important  lignite  in  this  field  is  that  marked  E  on  the  map. 
It  has  been  mined  for  local  supply  near  Dominy' s  ranch,  and  is  referred 
to  as  the  Dominy  lignite.  It  consists  of  a  group  of  lignite  beds  having 
a  vertical  range  of  about  30  feet,  some  or  all  of  which  are  workable 
wherever  they  have  not  been  destroyed  by  burning. 
Some  idea  of  the  former  extent  of  this  lignite  group  can  be  obtained 
from  the  distribution  of  the  baked  and  fused  material  caused  by  its 
burning,  from  which  it  is  inferred  that  lignite  beds  of  this  group 
formerly  covered  the  whole  area  here  described.  The  outcrop  of  these 
beds,  except  in  a  few  places,  is  completely  concealed  by  a  fringe  of 
clinker  and  baked  material,  which  reaches  in  many  localities  a  thick- 
ness of  100  feet.  The  areas  in  which  this  group  of  beds  has  not  been 
destroyed  are  relatively  small  and  many  of  them  are  difficult  to  locate. 
Between  Tongue  and  Powder  rivers  a  comparatively  large  area  in 
T.  7  N.,  Rs.  49  and  50  E.,  has  been  outlined,  as  shown  on  the  map 
(PI.  III).  The  average  thickness  of  workable  lignite  in  this  area  is 
thought  not  to  be  less  than  10  feet.  In  sec.  14,  T.  7  N.,  R.  49  E.,  it 
measures  15  feet,  and  in  sec.  28,  T.  7  N.,  R.  50  E.,  3  feet.  Another 
section  is  given  below: 
Section  of  Dominy  lignite  group  in  sec.  3,  T.  7  N.,  R.  50  E. 
Ft.    in. 
Lignite 7 
Shale,  sandy 13 
Lignite 3     6 
Shale,  sandy 8 
Lignite 5 
Total  lignile 15     6 
The  lowest  bench  of  this  section  is  represented  by  sample  No.  5962 
of  the  table  of  analyses  (p.  57). 
East  of  Powder  River  the  known  areas  of  the  Dominy  lignite,  as 
shown  by  the  map,  are  confined  to  T.  7  N.,  R.  53  E.,  near  the  town  of 
Knowlton.     Several  sections  of  the  beds  were  measured  here. 
Section  of  Dominy  lignite  bed  in  sec.  33,  T.  7  N.,  i?.  53  E. 
Ft.    in. 
Lignite,  dirty 6 
Lignite,  good 1    2 
Bone 4 
Lignite 2 
Parting,  sandy 1 
Lignite 1  10 
Total  lignite 5     6 
In  sec.  7,  T.  7  N.,  R.  53  E.,  4  feet  of  lignite  are  exposed  with  both 
top  and  bottom  concealed. 
