172        CONTRIBUTIONS   TO   ECONOMIC   GEOLOGY,   1907,   PART  II. 
with  which  for  convenience  is  included  a  small  coal  district  south  of 
Lovell;  (2)  the  Garland  coal  field,  north  and  east  of  Garland,  Wyo.; 
,  (3)  the  Silvertip  coal  field,  at  the  head  of  Silvertip  Creek,  20  miles 
south  of  Bridger,  Mont.,  and  (4)  the  Bridger  coal  field,  extending 
from  the  vicinity  of  Bridger  northward  beyond  Joliet,  Mont. 
BASIN  COAL  FIELD. 
The  Basin  field,  at  the  south  end  of  the  territory  mapped,  con- 
sists of  a  small  area  of  about  15  square  miles,  lying  on  both  sides  of  No 
Wood  Creek,  principally  east  of  Bighorn  River. 
Goal  in  Claggett  formation. — Coal  is  present  in  the  Claggett  forma- 
tion at  a  number  of  places  in  the  Basin  field,  but  has  no  economic 
value.     The  following  section  indicates  the  nature  of  the  coal  beds: 
Section  of  coal  beds  on  Dry  Creek,  2  miles  west  of  Grey  Bull,  Wyo. 
Ft.    in. 
Coal 4 
Bone 6 
.  Coal 4J 
Shale,  lignitic 1      6 
Shale,  carbonaceous,  and  sandstone 18 
Sandstone,  soft 1      6 
Coal,  bony 11 
From  this  locality  the  coal  has  been  traced  south-southeastward 
across  Grey  Bull  River,  2\  miles  above  the  town  of  Grey  Bull.  It  is 
exposed  near  the  railroad,  on  the  bank  of  a  small  creek  1  mile  south 
of  Basin.  Here  only  14  inches  of  coal  is  present,  and  south  of  this 
point  the  coal  disappears. 
Coal  in  Laramie  formation. — The  Laramie  coal  beds  are  well 
developed  in  the  Basin  field.  On  the  west  bank  of  Sand  Creek,  the 
southern  tributary  of  No  Wood  Creek,  they  outcrop  for  a  distance  of 
4  miles,  occurring  in  a  series  of  variegated  greenish-white  and  dark 
carbonaceous  shales.  The  shales  resemble  those  of  the  Judith  River 
formation,  both  in  appearance  and  in  being  very  soft,  so  that  valleys 
have  been  eroded  in  them.  The  coal  is  typically  shown  on  the  south 
bank  of  No  Wood  Creek,  1 J  miles  southwest  of  the  Jordan  mill,  where 
the  following  section  was  measured: 
Section  of  coal  bed  and  associated  rocks  on  the  south  bank  of  No  Wood  Creek,  Wyoming. 
Ft.    in. 
Sandstone,  gray 30 
Sandstone,  pure  white  (probably  base  of  Fort  Union) 12 
Shale,  dark,  carbonaceous  (Laramie?) 74 
Sandstone  and  sandy  shale 5 
Coal 4i 
Clay 1 
Coal  with  bony  streaks,  poor 1     11 
Totalcoal 2      3£ 
