402         CONTRIBUTIONS   TO    ECONOMIC   GEOLOGY,    1907,   PART   II. 
nt  the  north  on  Evans  Creek  in  T.  33  S.,  R.  2.  W.  of  the  Willamette 
principal  meridian,  stretches  to  the  south  and  southeast  in  the  Rogue 
River  Valley  east  of  Medford  and  Ashland,  and  continues  through  the 
Siskiyou  Mountain  divide  into  California,  a  total  distance  of  nearly 
100  miles. 
STRUCTURE   OF   COAL  BELT. 
The  Cascade  Range,  east  of  the  coal  belt,  is  made  up  mainly  of  Ter- 
tiary lavas;  the  Klamath  Mountains,  on  the  west,  are  composed  of 
granular  igneous  rocks  and  a  smaller  proportion  of  pre-Cretaceous 
sediments. 
The  soft  rocks  in  which  the  Rogue  River  valley  has  been  cut  are 
sandstones,  shales,  and  conglomerates.  They  dip  generally  eastward, 
extending  beneath  the  greater  portion  of  the  lava  fields  of  the  Cascade 
Range.  The  older  sediments  along  the  western  border  of  the  valley, 
by  Bear  Creek  from  the  Toll  House  to  Ashland,  Phoenix,  and  Jack- 
sonville, are  Cretaceous  in  age  and  do  not  contain  coal.  The  coal- 
bearing  rocks  lie  east  of  Bear  "Creek  as  far  north  as  Medford,  but 
beyond  that  point  they  overlap  the  Cretaceous  rocks  and  occupy  the 
whole  northern  portion  of  the  Rogue  River  valley. 
THE   COAL. 
The  principal  prospects  have  been  made  near  Medford  and  Ashland, 
but  others  occur  on  Evans  Creek,  to  the  north,  and  near  Ager,  in 
California,  to  the  south. 
PROSPECTS  ON  EVANS  CREEK. 
On  Evans  Creek  the  strata  dip  locally  to  the  northwest,  but  at  the 
time  of  examination  the  incline  by  which  the  coal  was  prospected  was 
full  of  water,  so  that  the  available  exposures  were  unsatisfactory. 
However,  there  appear  to  be  8  feet,  if  not  more,  of  coal,  some  of  which 
is  of  fair  quality,  but  most  of  which  is  impure  and  shaly.  The  coal 
bed  has,  besides  a  number  of  small  clay  partings,  two  prominent  part- 
ings of  sandstone,  one  12  inches  and  the  other  6  inches  thick.  The 
shaly  coal  has  been  sheared  so  that  much  of  it  is  slickensided  and 
goes  to  pieces  on  exposure.  The  immediate  vicinity  does  not  show 
a  large  body  of  coal  above  drainage  level.  The  coal  at  this  point 
appears  to  lie  within  a  few  hundred  feet  of  the  base  of  the  coal- 
bearing  rocks. 
Coal  is  reported  from  the  meadows  on  Evans  Creek  and  also  from 
Table  Mountain  on  Rogue  River,  but  as  there  was  no  active  prospect- 
ing at  either  locality  they  were  not  specially  examined. 
