27G         CONTRIBUTIONS    TO    ECONOMIC    GEOLOGY, 
No.  6  beds.  The  old  Van  Dyke  mine  was  located  on  the  bed  of 
the  same  name;  the  Union  Pacific  Coal  Company's  mines  Nos.  7,  8, 
9,  and  10  and  the  Central  Coal  and  Coke  Company's  mines  Nos.  1,  2, 
3,  4,  and  5  are  all  located  on  No.  7  bed;  the  Union  Pacific  Coal  Com- 
pany's mine  No.  1  and  old  mines  Nos.  2  and  4  on  No.  1  bed;  the 
Union  Pacific  Coal  Company's  mines  Nos.  3  and  5  on  No.  5  bed,  and 
old  mine  No.  6  on  No.  6  bed.  All  the  mines  on  these  coal  beds, 
except  those  on  Nos.  1  and  7,  have  been  abandoned  for  some  time. 
Only  one  mine — No.  1  of  the  Union  Pacific  Coal  Company — is  at 
present  working  No.  1  bed.  All  the  other  producing  mines  of  the 
Union  Pacific  Coal  Company,  Nos.  7,  8,  9,  and  10,  and  the  Central 
Coal  and  Coke  Company's  two  mines,  Nos.  2  and  5  (the  latter  com- 
prising what  is  left  of  mines  Nos.  1,3,  and  4,  as  well  as  the  new  No.  5 
slope),  are  working  No.  7  bed,  which  furnishes  a  greater  supply  of 
coal  than  any  other  bed  at  Rock  Springs.  No.  1  mine  of  the  Union 
Pacific  Coal  Company,  which  is  the  oldest  and  best-known  working 
mine  in  this  locality  and  produces  some  of  the  best  coal,  is  at  present 
1^  miles  down  the  slope  and  working  a  breast  of  coal  3  miles  long. 
As  Rock  Springs  does  not  lie  within  the  area  mapped  the  past 
summer,  no  further  detailed  description  of  the  Rock  Springs  mines 
will  be  given  in  this  paper,  although  they  were  all  visited  and  sam- 
ples of  coal  were  collected  for  analysis  at  all  of  them.  It  should  be 
stated,  however,  that  two  spur  tracks  are  being  built  from  the  main 
line  of  the  Union  Pacific  Railroad — one  northward  from  Rock  Springs 
up  Killpecker  valley,  the  other  northward  along  the  west  side  of 
Baxter  basin  from  a  point  west  of  Baxter  station  to  the  Gunn 
mining  camp,  in  T.  19  N.,  R.  104  W.,  where  a  new  mine  is  being 
opened  by  the  Gunn  Mining  Company. 
BLACK  BUTTES. 
At  Black  Buttes  a  mine  was  opened  soon  after  the  extension  of 
the  Union  Pacific  Railroad  into  this  region  in  1868.  Two  beds  of 
coal  were  worked  at  this  place  for  some  time.  The  upper  bed  is  4 
feet  thick;  the  main  bed,  15  feet  lower,  has  a  thickness  of  8  feet  and 
supplied  most  of  the  coal  while  the  mine  was  in  operation.  After  a 
short  period  of  activity  the  mine  was  abandoned,  as  better  coal  was 
obtained  in  the  vicinity  of  Rock  Springs. 
In  1907  the  Rock  Springs-Gibraltar  Coal  Company  opened  a  mine 
approximately  1  mile  southwest  of  the  old  Black  Buttes  mine  and 
on  the  same  coal  bed.  This  company  is  opening  two  coal  beds  at 
this  place;  the  upper,  6  feet  6  inches  thick,  is  the  main  bed,  and  78 
feet  below  this  occurs  a  second  bed  4  feet  6  inches  thick,  which  is 
also  being  developed;  13  feet  8  inches  below  the  second  is  another 
bed  of  good  coal  2  feet  2  inches  thick,  which  at  present  is  not  pros- 
pected. 
