A   RECONNAISSANCE  OF  THE  MINERAL  DEPOSITS   OF 
NEW  MEXICO. 
By  Waldemar  Lindgren  and  L.  C.  Graton. 
INTRODUCTION. 
A  general  reconnaissance  of  the  mineral  deposits  of  New  Mexico  was  undertaken  during 
the  field  season  of  1905.  The  two  principal  objects  in  view  were,  first,  to  obtain,  for  prac- 
tical purposes,  a  needed  summary  of  the  condition  of  the  mining  industry  throughout  the 
Territory,  and,  second,  to  develop  general  conclusions  bearing  on  the  origin  of  the  deposits. 
It  was  held  that  such  a  reconnaissance  would  bring  out  the  salient  facts  relating  to  genesis 
better  than  a  detailed  examination  of  one  or  two  of  the  larger  districts.  In  addition,  it 
was  expected  that  the  work  would  disclose  much  of  interest  and  value  regarding  the  general 
geology  and  serve  as  a  basis  for  a  preliminary  geological  map  of  the  Territory. 
Dr.  C.  H.  Gordon,  of  Socorro,  N.  Mex.,  examined  the  deposits  of  Sierra,  Socorro,  and  part 
of  Luna  counties.  Many  statements  based  on  his  work  will  be  found  in  the  following  pages. 
Mr.  F.  C.  Schrader,  of  the  United  States  Geological  Survey,  examined  a  number  of  copper 
deposits  in  the  northwestern  part  of  the  State. 
A  summary  of  the  facts  ascertained  and  some  of  the  conclusions  drawn  from  them  are 
contained  in  this  article,  which  is  simply  a  preliminary  statement,  possibly  to  be  modified 
by  the  more  detailed  study  of  collections  and  notes  now  in  progress. 
GENERAL    GEOLOGY. 
PHYSIOGRAPHIC   PROVINCKS. 
New  Mexico  is  divisible  into  four  more  or  less  distinct-  regions  or  provinces,  the  division 
being  based  on  the  character  of  the  surface  of  the  country. 
The  northwestern  portion  of  the  Territory  is  a  diversified  plateau  region  which,  extend- 
ing across  northeastern  Arizona  and  southwestern  Colorado  into  Utah,  forms  part  of  the 
Great  Interior  Plateau  of  the  western  United  States.  This  plateau  has  been  considerably 
modified  by  recent  erosion,  but  presents  in  broad  view  a  fairly  flat  expanse  of  large  extent. 
To  the  south  of  the  great  plateau  and  separated  from  it  by  a  somewhat  indistinct  bound- 
ary is  the  region  of  desert  ranges.  This  province  occupies  nearly  the  whole  of  the  south- 
western quarter  of  New  Mexico.  It  extends  southward  into  Mexico  and,  sweeping  diagonally 
across  central  Arizona,  connects  with  the  Basin  Ranges  of  Utah  and  Nevada.  This  province 
is  characterized  by  broad  Quaternary  desert  plains,  through  which  protrude  isolated  knobs, 
clusters  of  peaks,  and  comparatively  short  ranges.  The  latter  extend  in  generally  parallel 
north-south  directions,  but  they  can  not  be  correlated  into  any  system. 
Bounding  the  great  plateau  and  the  desert-range  province  on  the  east  the  central  moun- 
tain belt  extends  along  the  middle  of  New  Mexico  and  is  one  of  the  most  important  physio- 
graphic features  of  the  Territory.  To  the  south  it  is  represented  by  ranges  along  the  Rio 
Grande  in  Texas  and  Mexico  and  to  the  north  it  merges  into  the  Sangre  de  Crist  o  Range  of 
Colorado,  and  thus  constitutes  the  southerly  extension  of  the  Rocky  Mountains.     The  main 
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