336         CONTRIBUTIONS   TO    ECONOMIC  GEOLOGY,   1907,   PART   II. 
and  to  be  represented  by  more  or  less  eroded  hogbacks,  with  inter- 
vening valleys  of  softer  Lewis  shale.  This  relationship  extends  from 
Durango  eastward  to  Monero,  and  thence  southward  to  the  vicinity  of 
Gallina,  where  the  Laramie  was  found  to  be  no  longer  marked  by  a 
prominent  hogback,  but  to  be  more  or  less  covered  by  overlapping 
Tertiary  rocks.  This  complexity  of  structure,  together  with  lack  of 
time,  compelled  the  party  to  discontinue  the  mapping  of  the  Laramie 
at  this  place,  and  it  was  not  recognized  beyond  this  point.  The 
Mesaverde  formation,  being  more  resistant  and  covered  to  a  less 
extent  by  unconformable  shale,  was  easily  followed  southward. 
In  Shaler's  reconnaissance  in  1906  the  Mesaverde  and  Laramie 
formations  were  recognized  in  similar  relationship  around  the  west 
sicfe  of  the  basin  to  the  vicinity  of  Sulphur  Spring,  on  the  drainage 
of  Rio  Chaco.  Here  the  Mesaverde  and  Laramie  boundaries  were 
found  to  diverge,  the  former  continuing  southward,  the  latter  bearing 
off  to  the  east  a  short  distance  north  of  Rio  Chaco.  The  Laramie  was 
traced  and  mapped  as  far  east  as  Raton  Spring,  about  35  miles  west 
of  Gallina.  At  this  point  the  examination  of  the  Laramie  was 
abandoned,  but  it  appeared  to  continue  eastward  to  the  region  near 
Gallina,  where  Schrader  last  recognized  it  a  year  previous. 
The  present  report  covers  the  area  between  Gallina  and  Raton 
Spring.  The  field  work  was  carried  on  from  July  20  to  August  26, 
inclusive,  1907,  by  the  writer,  assisted  by  William  J.  Reed  and  Albert 
L.  Beekly.  To  these  gentlemen  acknowledgments  are  due  for  valu- 
able assistance  in  the  field  and  office.  The  map  (PI.  XXII)  pre- 
sented in  connection  with  this  report  was  prepared  by  Mr.  Reed. 
GEOGRAPHY  AND  TOPOGRAPHY. 
Gallina,  N.  Mex.,  is  a  small  Mexican  settlement  of  about  100  people, 
located  approximately  in  latitude  36°  15'  and  longitude  106°  50',  at 
the  point  where  Gallina  River  emerges  from  the  Sierra  Nacimiento. 
About  14J  miles  south-southwest  is  the  old  Mexican  town  of  Naci- 
miento, known  to  the  post-office  officials  as  Cuba.  This  village  con- 
tains about  200  inhabitants,  and  is  located  in  a  small  fertile  valley  at 
the  foot  of  San  Pedro  Mountain,  near  the  point  where  Nacimiento 
Creek  joins  Rio  Puerco.  Lajara,  Copper  City,  and  Senorito  are 
settlements  of  less  importance.  About  34  miles  south  of  west  from 
Cuba  is  Raton  Spring,  where  there  are  two  Mexican  stores  and  a  few 
dwelling  houses.  Raton  Spring  is  known  also  as  Pueblo  Pintado,  a 
name  formerly  applied  to  the  Aztec  ruins,  which  are  still  evident  at 
this  place.  The  spring  itself  is  a  deep  pool  of  somewhat  alkaline 
water,  which  flows  as  a  mere  seep.  At  Ensino  Spring,  between  Cuba 
and  Raton,  11  miles  north  of  east  from  Raton,  there  are  some  Indian 
stone  huts,  but  the  spring  is  known  as  a  watering  place  for  miles  over 
