THE  DURANGO-GALLUP  COAL  FIELD  OF  COLORADO 
AND  NEW  MEXICO. 
By  F.  C.  Sciiradek. 
LOCATION. 
The  Durango-Gallup  coal  field  lies  mainly  in  the  northwestern  part  of  New  Mexico, 
but  includes  also  a  small  area  in  the  southwestern  part  of  Colorado.  As  shown  by  the  encir- 
cling outcrop  of  its  coal-bearing  rocks  on  the  accompanying  map&  (PI.  VII),  it  extends  from 
Durango,  Colo.,  on  the  north,  beyond  Gallup  and  Mount  Taylor  in  New  Mexico,  on  the  south, 
and  from  near  the  New  Mexico-Arizona  line,  on  the  west,  to  Chama,  Elvado,  and  the  Sierra 
Nacimiento,  near  the  longitude  of  Albuquerque,  on  the  east. 
It  is  situated  in  the  great  Plateau  Province  described  by  Powell  and  Dutton,  and  includes 
most  of  the  upper  part  of  the.  basin  of  San  Juan  River,  which  drains  westward  and  forms 
one  of  the  most  important  tributaries  of  the  Colorado.  A  small  area  in  the  southwestern 
part  of  the  field,  including  the  region  about  Gallup,  also  drains  to  the  west  by  way  of  Rio 
Puerco  and  the  Little  Colorado.  Although  located  mainly  on  the  western  slope,  the  field 
extends  across  the  continental  divide,  whence  the  drainage  from  its  southeastern  border 
finds  an  outlet  by  way  of  Chama  and  San  Jose  rivers  and  the  Rio  Grande  into  the  Gulf  of 
Mexico. 
The  area  thus  defined  comprises  the  principal  part  of  the  coal  field  as  known,  but  the 
coal-bearing  rocks  extend  to  the  northwest  and  west  into  Utah  and  Arizona,  and  also  to 
the  south  50  or  60  miles  beyond  Gallup.  As  these  outlying  areas  were  not  visited  during 
last  season,  they  will  not  be  given  further  consideration  in  this  paper. 
Geographically  the  field  may  be  characterized  as  a  dissected  plateau — a  diversified  land 
of  mountains,  buttes,  mesas,  terraces,  ridges,  scarps,  valleys,  canyons,  and  arroyos,  in 
which  the  deeper  valleys  are  nearly  1,000  feet  below  the  general  upland  level.  The  highest 
'mountains  are  on  the  north  and  east,  and  from  these  summits  the  surface  slopes  gently  to 
the  west  down  the  valley  of  San  Juan  River.  The  elevations,  which  vary  from  nearly  9,000 
feet  on  the  continental  divide  to  5,000  feet  in  San  Juan  Valley,  are  estimated  to  average 
about  6,500  feet. 
The  occurrence  of  coal  at  various  points  in  the  field  has  been  known  for  more  than  half 
a  century  through  the  work  of  Wheeler,  Hay  den,  and  other  early  explorers.  In  1892 
R.  C.  Hills  published  in  Mineral  Resources  of  the  United  States  an  account  of  that  part  of 
the  field  which  lies  in  Colorado,  and  in  1902  L.  S.  Storrs  prepared  and  published  in  the 
(Twenty-second  Annual  Report  of  the  Survey  an  account  of  the  entire  field  in  both  Colorado 
and  New  Mexico. 
Coal  has  been  mined  for  a  score  or  more  years  at  Durango  and  Monero,  in  the  northern 
part  of  the  field,  and  at  Gallup  and  Clarksville,  in  the  southern  part.  The  field  as  a  whole 
is  very  important  on  account  of  its  nearness  to  the  mining  centers  of  Arizona  and  the  South- 
west, where  coal  of  any  consequence  is  unknown. 
a  This  preliminary  report  is  to  be  followed  by  a  fuller  description  of  the  field,  now  in  preparation, 
which  will  appear  as  a  bulletin  of  the  Survey. 
t>  This  map  was  prepared  by  Mr.  M.  K.  Shaler. 
241 
