COAL   BETWEEN   GALLTNA  AND   RATON    SPRING,    X.    MEX.         34l 
Lajara;  and  along  the  foot  of  San  Pedro  Mountain  east  of  Cuba  the 
rocks  are  overturned  and  dip  70°  E.  The  highly  tilted  Puerco  and 
Torrejon  indicate  an  elevation  of  the  Sierra  Nacimiento  after  their 
deposition.  This  elevation  took  place  at  the  close  of  Torrejon  time, 
as  shown  by  the  fact  that  the  superjacent  Wasatch  beds  lie  appar- 
ently level  against  the  mountain. 
There  are  two  prominent  unconformities  by  overlap  in  the  beds 
above  the  Laramie- — one  at  the  base  of  the  Puerco,  the  other  at  the 
base  of  the  Wasatch.  The  relation  of  these  unconformities,  dips,  etc., 
may  be  obtained  from  the  accompanying  map  (PI.  XXII).  In  the 
vicinity  of  Ensino  Spring  and  of  the  lake  7  miles  north  of  east  from 
the  spring  there  are  local  domes  in  the  strata.  Such  local  changes  in 
dips  prevent  an  accurate  estimate  of  thickness  by  topographic  lines 
on  the  map.  As  discussed  under  the  heading  "  Tertiary  rocks," 
there  is  also  very  strong  evidence  of  an  unconformity  between  the 
Puerco  and  the  overlying  Torrejon. 
There  are  few  faults  aside  from  local  displacements  along  the  east 
side  of  the  field  adjacent  to  the  mountains.  Many  such  minor  dislo- 
cations occur  along  the  strike  of  the  sedimentary  beds  where  they  rest 
in  close  proximity  to  the  crystalline  rocks,  but  they  are  not  of  sufficient 
importance  for  discussion  here.  The  only  fault  deserving  mention  is 
the  one  at  Raton  Spring.  This  is  a  tension  fault  with  a  stratigraphic 
throw  of  60  feet.  The  strike  is  inconstant,  but  averages  about  S.  50° 
E.  from  the  spring  for  a  distance  of  several  miles,  the  downthrow 
being  on  the  northeast  side.  The  spring  issues  near  the  fault  and 
doubtless  has  its  source  along  the  fault  plane. 
THE   COAL. 
COAL-BEARING   FORMATIONS. 
The  two  coal-bearing  formations  are  the  Mesaverde  and  the  Lara- 
mie. Coal  has  been  mined  in  this  field  from  the  former  only,  and 
that  to  a  very  slight  extent  in  one  locality.  One  mile  southwest  of 
Senorito  the  upper  bed  of  the  Mesaverde  has  been  opened  and  mined 
for  local  use  by  the  Juratrias  and  other  copper  companies,  which  have 
now  discontinued  operations.  The  coal  was  used  for  steaming  and 
smelting  as  well  as  for  domestic  purposes,  and  is  reported  to  have 
given  general  satisfaction. 
The  Laramie  is  covered  by  the  overlap  of  the  Tertiary  in  the 
vicinity  of  Gallina,  on  the  north  side  of  the  field.  At  this  point  it  is 
barren  of  workable  coal  beds.  Its  boundary  beneath  the  Tertiary 
diverges  from  that  of  the  north-south  line  of  the  Mesaverde,  and  at 
its  reappearance  on  the  south  side  of  the  field  is  about  12  miles  west 
of  the  Mesaverde  boundary.  From  this  point  the  strike  turns  west- 
ward and  the  formations  begin  to  show  thin  coal  beds  which  increase 
in  thickness  and  number  toward  Raton  Spring. 
