THE  GRAND  MESA  COAL  FIELD,  COLORADO, 
By  Willis  T.  Lee. 
INTRODUCTION. 
LOCATION   OF  THE  FIELD. 
The  Grand  Mesa  coal  field  is  located  on  the  southern  rim  of  the 
Uinta  coal  basin,  which  lies  partly  in  northwestern  Colorado  and 
partly  in  Utah.  It  derives  its  name  from  Grand  Mesa,  a  high  table- 
land between  Grand  and  Gunnison  rivers.  The  coal  beds  underlie 
the  mesa  and  outcrop  along  the  south  and  west  sides.  They  extend 
westward  into  the  Book  Cliffs  field,  north  of  Grand  Junction,0  and 
eastward  into  the  Anthracite-Crested  Butte  region,6  long  known  for 
its  anthracite  coal,  and  thence  northward  along  the  Grand  Hogback, 
recently  described  by  Gale.c 
PURPOSE  OF  THE   INVESTIGATION. 
The  investigation  of  this  field  was  undertaken  for  the  purpose,  first, 
of  ascertaining  the  relations  of  the  coal-bearing  rocks  to  other  forma- 
tions; second,  of  segregating  the  coal  land  from  the  noncoal  land  and 
classifying  it  according  to  the  legal  subdivisions  of  the  General  Land 
Office;  and,  third,  of  determining  the  thickness  of  the  coal  beds,  the 
character  and  quality  of  the  coal,  its  accessibility  with  reference  to 
topography  and  its  location  with  reference  to  lines  of  transportation. 
The  economic  results  of  the  investigation  are  summarized  in  this 
paper.  Details  and  the  results  of  scientific  importance  will  be  found 
in  a  more  comprehensive  paper  to  be  published  later  as  a  separate 
bulletin, 
METHODS   OF  WORK. 
The  Grand  Mesa  field  is  comparatively  free  from  complicated  struc- 
tures, and  the  geologic  work  consisted  principally  in  determining 
the  ages  and  areal  distribution  of  the  sedimentary  rocks.     Samples 
a  Richardson,  G.  B.,  The  Book  Cliffs  coal  field,  between  Grand  River,  Colorado,  and  Sunnyside, 
Utah;  Bull.  U.  S.  Geol.  Survey  No.  316, 1907,  pp.  302-320. 
fc  Eldridge,  G.  H.,  Anthracite-Crested  Butte  folio  (No.  9),  Geologic  Atlas  U.'S.,  U.  S.  Geol.  Survey, 
1894. 
c  Gale,  H.  S.,  Coal  fields  of  the  Danforth  Hills  and  Grand  Hogback  in  northwestern  Colorado:  Bull. 
U.  S.  Geol.  Survey  No.  316,  1907,  pp.  264-301. 
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