390        CONTRIBUTIONS  TO  ECONOMIC  GEOLOGY,  1907,  PART  II. 
The  Jones  mine  (No.  la)  is  situated  in  the  NW.  \  sec.  36,  T.  36  S., 
B,.  10  W.,  about  25  feet  above  Coal  Creek  and  adjacent  to  a  good 
wagon  road.  Like  all  the  workings  in  this  field,  this  mine  consists  of 
a  tunnel  driven  in  on  the  outcrop  for  100  feet,  more  or  less.  The 
following  section  was  measured  in  the  mine: 
Section  of  coal  bed  at  Jones  mine. 
Limestone,  fossiliferous.  Ft.      in. 
Shale,  carbonaceous 1 
Coal 1    8-12 
Bone 1-  4 
Coal .- 2    3-12 
Shale,  carbonaceous 3 
Limestone,  fossiliferous. 
Total  coal 5± 
The  Jensen  mine  (No.  2)  is  an  abandoned  drift  about  three-fourths 
of  a  mile  northwest  of  the  Jones  property,  in  the  NE.  \  sec.  35, 
T.  36  S.,  R.  10  W.  The  workings  were  inaccessible  in  the  summer  of 
1907,  and  the  thickness  of  the  coal  was  not  determined. 
A  fault  apparently  causes  an  offset  of  the  coal  in  sees.  27  and  28,  as 
shown  on  the  map,  where  the  vertical  displacement  between  two 
beds  of  coal,  presumably  the  same,  is  indicated  as  about  700  feet. 
At  a  prospect  in  the  downthrown  block  in  the  SE.  \  sec.  28,  T.  36  S., 
R.   10  W.,  the  following  section  was  measured: 
Section  of  coal  bed  in  prospect  south  of  Coal  Creek. 
Shale.  Ft.    in. 
Coal 6 
Bone 4 
Coal 3 
Bone 1 
Coal 10 
Limestone,  fossiliferous. 
Total  coal  and  bone 5      8 
A  number  of  prospects  have  been  opened  on  the  coal  in  sec.  33, 
T.  36  S.,  R.  10  W.  The  abandoned  Leyson  mine  (No.  3)  is  reported  to 
have  been  the  earliest  opened  in  this  field,  and  to  have  been  worked 
between  1854  and  1890.  Daggett6  states  that  the  bed  in  this  mine 
is  split  by  a  clay  parting  into  an  upper  bench  2  feet  thick  and  a  lower 
one  4  feet  thick. 
.  At  the  Wood  prospect  (No.  4),  about  half  a  mile  to  the  south,  the 
following  section  was  measured  by  W.  T.  Lee : 
a  The  numbers  refer  to  location  of  mines  and  prospects  on  PI.  XXV. 
t>  Daggett,  E.,  Analyses  and  calorific  values  of  some  Utah  coals:  Mineral  Resources  U.  S.,  U.  S.  Geol. 
Survey,  1883,  p.  77. 
