﻿100 
  C. 
  L. 
  Baker 
  — 
  Contributions 
  to 
  the 
  

  

  each 
  characterized 
  by 
  one 
  long 
  gentle 
  dip 
  slope 
  with 
  an 
  

   opposite 
  facing 
  escarpment 
  of 
  much 
  greater 
  dip 
  and 
  in 
  

   some 
  cases, 
  at 
  least, 
  locally 
  broken 
  by 
  upthrust 
  faults. 
  

   It 
  is 
  probable, 
  however, 
  that 
  not 
  all 
  of 
  these 
  steep 
  escarp- 
  

   ments 
  are 
  fault 
  scarps. 
  In 
  most 
  places 
  erosion 
  is 
  top 
  far 
  

   advanced 
  to 
  exhibit 
  the 
  usual 
  physiographic 
  criteria 
  of 
  

   fault 
  scarps. 
  The 
  western 
  of 
  the 
  three 
  great 
  anticlines 
  

   of 
  the 
  Basin 
  Ranges 
  begins 
  on 
  the 
  north 
  with 
  the 
  Sandia 
  

   Mountains, 
  northwest 
  of 
  Albuquerque, 
  continues 
  to 
  the 
  

   south 
  in 
  the 
  Manzano 
  Mountains, 
  thence 
  swings 
  south- 
  

   west 
  in 
  the 
  Sierra 
  de 
  los 
  Pinos 
  and 
  gradually 
  decreases 
  

   in 
  altitude 
  towards 
  Socorro 
  on 
  the 
  Rio 
  Grande. 
  The 
  es- 
  

   carpment 
  in 
  these 
  ranges 
  faces 
  the 
  valley 
  of 
  the 
  Rio 
  

   Grande. 
  The 
  intermediate 
  structural 
  axis 
  begins 
  on 
  the 
  

   north 
  with 
  the 
  Sierra 
  Oscura 
  with 
  steep 
  scarp 
  on 
  the 
  

   west, 
  forms 
  a 
  faulted 
  anticline 
  in 
  the 
  Little 
  Burro 
  Moun- 
  

   tains, 
  south 
  of 
  which 
  the 
  scarp 
  passes 
  to 
  the 
  east 
  side 
  in 
  

   the 
  San 
  Andreas 
  Mountains 
  and 
  continues 
  thus 
  south- 
  

   wards 
  into 
  the 
  Organ 
  and 
  Franklin 
  mountains; 
  the 
  

   structure 
  coming 
  to 
  an 
  end 
  at 
  El 
  Paso, 
  Texas. 
  The 
  

   easternmost 
  main 
  structure 
  rises 
  on 
  the 
  north 
  out 
  of 
  

   the 
  synclinal 
  basin 
  of 
  Upper 
  Cretaceous 
  sediments 
  and 
  

   igneous 
  rocks 
  of 
  the 
  Sierra 
  Blanca 
  massif 
  into 
  the 
  Sacra- 
  

   mento 
  Mountains 
  overlooking 
  with 
  steep 
  western 
  scarp 
  

   the 
  Tularosa 
  Basin, 
  then 
  swings 
  east 
  of 
  south 
  in 
  the 
  

   southern 
  Sacramentos, 
  in 
  the 
  southern 
  extremity 
  of 
  

   which 
  it 
  gives 
  off 
  several 
  low 
  folds 
  continuing 
  southward 
  

   into 
  the 
  Hueco 
  Mountains, 
  the 
  main 
  axis 
  being 
  shifted 
  

   many 
  miles 
  to 
  the 
  east 
  into 
  the 
  Guadalupe 
  Mountains. 
  

   In 
  the 
  northern 
  part 
  of 
  the 
  latter 
  range 
  the 
  anticline 
  

   passes 
  for 
  a 
  short 
  distance 
  into 
  an 
  upthrust 
  fault 
  with 
  

   displacement 
  at 
  a 
  maximum 
  of 
  over 
  1000 
  feet, 
  thence 
  

   southward 
  passes 
  into 
  an 
  anticline 
  with 
  northwest- 
  south- 
  

   east 
  axis 
  and 
  steeper 
  dip 
  on 
  the 
  southwest 
  flank, 
  again 
  

   passing 
  into 
  an 
  upthrust 
  fault 
  near 
  the 
  Texas 
  line 
  which 
  

   continues 
  as 
  a 
  fault 
  to 
  a 
  short 
  distance 
  south 
  of 
  Guada- 
  

   lupe 
  Point, 
  thence 
  apparently 
  passing 
  into 
  an 
  anticline 
  

   in 
  the 
  northern 
  Delaware 
  Mountains 
  of 
  Texas 
  and 
  ending 
  

   in 
  a 
  southward-plunging 
  broad-ended 
  anticline 
  in 
  the 
  

   vicinity 
  of 
  the 
  Texas 
  and 
  Pacific 
  Railway. 
  The 
  gentle 
  

   eastward 
  dip 
  slope 
  of 
  the 
  Sacramento 
  Mountains 
  is 
  70 
  

   miles 
  broad 
  between 
  Cloudcroft 
  and 
  Roswell, 
  and 
  the 
  

   same 
  general 
  dip, 
  becoming 
  less 
  in 
  amount, 
  extends 
  east- 
  

   ward 
  for 
  probably 
  a 
  hundred 
  miles 
  farther. 
  The 
  Sacra- 
  

  

  