﻿110 
  C. 
  L. 
  Baker 
  — 
  Contributions 
  to 
  the 
  

  

  The 
  exposed 
  Abo 
  strata 
  in 
  the 
  Coyote 
  Basin, 
  west 
  flank 
  

   of 
  Sacramento 
  Mountains 
  at 
  their 
  north 
  end 
  five 
  miles 
  

   north 
  of 
  Tularosa, 
  have 
  a 
  thickness 
  of 
  about 
  1400 
  feet, 
  

   the 
  base 
  not 
  being 
  exposed 
  there. 
  This 
  section 
  is 
  charac- 
  

   terized 
  by 
  the 
  presence 
  of 
  heavy 
  arkose, 
  interbedded 
  with 
  

   sandstones, 
  clayey 
  and 
  shaly 
  sands 
  and 
  fossiliferous 
  

   limestones. 
  In 
  the 
  Juniper 
  Tank 
  section 
  of 
  the 
  southern 
  

   Sacramento 
  Mountains, 
  the 
  entire 
  thickness 
  of 
  the 
  Abo 
  

   is 
  only 
  350 
  feet, 
  the 
  upper 
  two 
  thirds 
  of 
  which 
  is 
  mainly 
  

   thin- 
  to 
  medium-bedded 
  blue-gray 
  limestone. 
  The 
  ex- 
  

   posures 
  in 
  the 
  central 
  and 
  northern 
  San 
  Andreas 
  Moun- 
  

   tains 
  do 
  not 
  greatly 
  differ 
  from 
  that 
  at 
  Juniper 
  Tank. 
  

  

  The 
  Abo 
  of 
  the 
  southern 
  San 
  Andreas 
  Range 
  rests 
  on 
  

   the 
  massive 
  cliff-forming 
  limestone 
  of 
  the 
  lower 
  Magda- 
  

   lena. 
  The 
  Abo 
  here 
  consists 
  of 
  medium-bedded 
  brown 
  

   and 
  greenish 
  brown 
  sandstone 
  interbedded 
  with 
  fossili- 
  

   ferous 
  limestones. 
  The 
  sandstone 
  is 
  calcareous 
  and 
  usu- 
  

   ally 
  shaly. 
  These 
  strata 
  are 
  about 
  1000 
  feet 
  thick. 
  

  

  Little 
  of 
  definite 
  value 
  can 
  be 
  said 
  concerning 
  the 
  age 
  

   of 
  the 
  Abo 
  until 
  the 
  fossil 
  collections 
  from 
  south-central 
  

   and 
  central-southern 
  New 
  Mexico 
  have 
  been 
  fully 
  studied. 
  

   A 
  large 
  collection 
  of 
  fossils 
  made 
  one 
  mile 
  east 
  of 
  the 
  

   business 
  center 
  of 
  the 
  town 
  of 
  Tularosa, 
  from 
  strata 
  

   about 
  200 
  feet 
  above 
  the 
  base 
  of 
  the 
  Abo, 
  contained 
  sev- 
  

   eral 
  species 
  of 
  ammonoids 
  which 
  Dr. 
  Bose 
  correlates 
  with 
  

   about 
  the 
  same 
  horizon 
  as 
  the 
  ammonoids 
  from 
  the 
  Cisco 
  

   formation 
  at 
  Graham, 
  Young 
  County, 
  Texas. 
  

  

  Yeso 
  Formation. 
  — 
  The 
  Yeso 
  formation 
  is 
  characterized 
  

   by 
  the 
  presence 
  of 
  bedded 
  gypsum. 
  In 
  central 
  New 
  

   Mexico 
  it 
  is 
  mainly 
  red 
  beds 
  with 
  gypsum 
  and 
  thin-bed- 
  

   ded, 
  siliceous, 
  fine-grained, 
  blue-gray, 
  limestones. 
  In 
  its 
  

   southernmost 
  outcrops, 
  limestones 
  largely 
  replace 
  red 
  

   beds, 
  and 
  the 
  amount 
  of 
  gypsum 
  greatly 
  decreases. 
  The 
  

   Yeso 
  is 
  not 
  found 
  about 
  the 
  flanks 
  of 
  the 
  Sangre 
  de 
  Cristo 
  

   Mountains. 
  Farther 
  south 
  it 
  is 
  exposed 
  over 
  vast 
  areas 
  

   of 
  rather 
  featureless 
  plains 
  with 
  sink-hole 
  topography. 
  

   It 
  rests 
  directly 
  on 
  the 
  crystallines 
  of 
  central 
  New 
  Mexico 
  

   and 
  overlies 
  the 
  Abo 
  on 
  the 
  flanks 
  of 
  the 
  Sandia, 
  Man- 
  

   zano, 
  Los 
  Pinos, 
  Oscura, 
  and 
  San 
  Andreas 
  and 
  Sacra- 
  

   mento 
  mountains. 
  It 
  makes 
  up 
  most 
  of 
  the 
  surface 
  ex- 
  

   posures 
  of 
  the 
  Chupadero 
  Mesa 
  and 
  is 
  exposed 
  beneath 
  

   the 
  Upper 
  Trias 
  in 
  the 
  anticlinal 
  axes 
  along 
  the 
  Pecos 
  

   River 
  from 
  Ribera 
  southwards 
  to 
  beyond 
  Puerto 
  de 
  Luna 
  

   and 
  in 
  Canon 
  Blanco, 
  a 
  tributary 
  entering 
  the 
  Pecos 
  a 
  

  

  