﻿112 
  C. 
  L. 
  Baker 
  — 
  Contributions 
  to 
  the 
  

  

  a 
  small 
  Productus, 
  and 
  crinoid 
  stems. 
  On 
  weathered 
  

   surfaces 
  the 
  limestone 
  has 
  almost 
  entirely 
  dissolved 
  out 
  

   and 
  has 
  left 
  narrow 
  oval 
  cavities 
  between 
  the 
  cherts. 
  

  

  Distinctive 
  fossils 
  prove 
  the 
  age 
  of 
  the 
  Yeso 
  to 
  be 
  lower 
  

   Permian 
  (Artinskian). 
  

  

  San 
  Andreas 
  Limestone. 
  — 
  The 
  maximum 
  thickness 
  of 
  

   the 
  San 
  Andreas 
  limestone 
  is 
  found 
  only 
  in 
  the 
  Guada- 
  

   lupe 
  and 
  Sacramento 
  mountains 
  and 
  in 
  wells 
  in 
  the 
  Pecos 
  

   Valley 
  east 
  of 
  the 
  mountains, 
  where 
  it 
  reaches 
  1100 
  feet. 
  

   The 
  original 
  thickness 
  of 
  the 
  San 
  Andreas 
  limestone 
  is 
  

   unknown, 
  as 
  it 
  is 
  everywhere 
  unconformably 
  overlain 
  

   either 
  by 
  other 
  lower 
  Permian 
  or 
  later 
  strata. 
  

  

  Caverns 
  in 
  the 
  San 
  Andreas 
  limestone 
  form 
  channels 
  

   for 
  the 
  artesian 
  water 
  of 
  the 
  lower 
  Pecos 
  Valley 
  of 
  New 
  

   Mexico. 
  

  

  The 
  San 
  Andreas 
  is 
  not 
  known 
  north 
  of 
  the 
  line 
  of 
  the 
  

   Belen 
  cut-off 
  of 
  the 
  Santa 
  Fe 
  Railroad. 
  It 
  is 
  found 
  in 
  

   the 
  uplifts 
  of 
  the 
  Los 
  Pinos, 
  San 
  Andreas, 
  Sacramento 
  

   and 
  Guadalupe 
  mountains. 
  It 
  forms 
  the 
  cap 
  rock 
  of 
  

   much 
  of 
  the 
  extensive 
  area 
  occupied 
  by 
  the 
  Chupadero 
  

   Mesa 
  and 
  its 
  outliers 
  and 
  has 
  been 
  brought 
  to 
  the 
  surface 
  

   by 
  the 
  large 
  intrusive 
  mass 
  of 
  the 
  Capitan 
  Mountains. 
  

   It 
  forms 
  the 
  surface 
  of 
  the 
  long 
  eastern 
  dip 
  slope 
  of 
  the 
  

   Sacramento 
  and 
  northern 
  Guadalupe 
  mountains 
  and 
  of 
  

   the 
  country 
  farther 
  north, 
  east 
  of 
  Torrance 
  and 
  Corona. 
  

   Its 
  base 
  is 
  often 
  marked 
  by 
  a 
  bed 
  of 
  saccharoidal 
  cream- 
  

   colored 
  sandstone, 
  fully 
  200 
  feet 
  thick. 
  Aside 
  from 
  this 
  

   the 
  San 
  Andreas 
  is 
  entirely 
  limestone, 
  generally 
  heavy- 
  

   bedded 
  and 
  very 
  hard. 
  Chert 
  is 
  entirely 
  wanting 
  in 
  

   some 
  localities 
  and 
  very 
  abundant 
  in 
  others. 
  Lee 
  Hager 
  

   reports 
  that 
  the 
  upper 
  beds 
  a 
  few 
  miles 
  west 
  of 
  Roswell 
  

   are 
  bituminous. 
  Geodes 
  of 
  calcite 
  are 
  quite 
  character- 
  

   istic 
  of 
  the 
  limestone. 
  The 
  fossils 
  are 
  generally 
  large 
  

   forms 
  of 
  Productus, 
  Spirifer, 
  Bellerophon, 
  Euomphalus 
  , 
  

   nautiloids, 
  corals, 
  echinoid 
  spines 
  and 
  crinoid 
  stems. 
  

  

  The 
  Giiadalupian-Pecos 
  Valley 
  Bed 
  Beds. 
  — 
  The 
  Gua- 
  

   dalupian 
  strata 
  outcrop 
  in 
  the 
  Guadalupe 
  Mountains 
  and 
  

   along 
  the 
  foot 
  of 
  the 
  east 
  flank 
  of 
  the 
  Sacramento 
  Moun- 
  

   tains, 
  and 
  underlie 
  the 
  alluvium 
  in 
  the 
  lower 
  Pecos 
  Val- 
  

   ley 
  of 
  New 
  Mexico. 
  Southward 
  in 
  Texas 
  they 
  have 
  a 
  

   great 
  development 
  in 
  the 
  Guadalupe, 
  Delaware, 
  Glass 
  

   and 
  Chinati 
  mountains. 
  The 
  Guadalupian 
  unconform- 
  

   ably 
  overlies 
  older 
  anthracolithic 
  strata. 
  The 
  following 
  

   section 
  shows 
  the 
  stratigraphic 
  relationships 
  of 
  the 
  Gua- 
  

  

  