﻿Stratigraphy 
  of 
  Eastern 
  New 
  Mexico. 
  103 
  

  

  tion 
  of 
  the 
  lower 
  Permian 
  lies 
  directly 
  upon 
  them; 
  and 
  

   in 
  places 
  in 
  the 
  Sangre 
  de 
  Cristo 
  Range 
  the 
  Abo 
  forma- 
  

   tion 
  of 
  the 
  late 
  Pennsylvanian 
  rests 
  directly 
  npon 
  them. 
  

  

  The 
  Paleozoic 
  Succession. 
  

  

  Early 
  Paleozoic 
  Sedimentary 
  Plochs. 
  — 
  Early 
  Paleozoic 
  

   strata, 
  though 
  well 
  distributed 
  in 
  southwestern 
  New 
  

   Mexico 
  and 
  Trans-Pecos 
  Texas, 
  are 
  found 
  only 
  in 
  the 
  

   central 
  southern 
  part 
  of 
  the 
  region 
  here 
  treated 
  : 
  in 
  the 
  

   southern 
  San 
  Andreas 
  and 
  Sacramento 
  mountains, 
  in 
  

   the 
  Organ 
  Mountains, 
  and 
  in 
  the 
  Fra 
  Cristobal 
  and 
  Los 
  

   Caballos 
  mountains 
  bordering 
  the 
  Eio 
  Grande. 
  The 
  only 
  

   detailed 
  section 
  made 
  is 
  that 
  of 
  the 
  southern 
  Sacramento 
  

   Mountains. 
  Here 
  supposedly 
  Pre-Cambrian 
  plutonics, 
  

   but 
  with 
  the 
  upper 
  contact 
  not 
  well 
  exposed, 
  are 
  followed 
  

   in 
  upward 
  succession 
  by 
  quartzites, 
  quartzose 
  sandstones 
  

   and 
  quartzose 
  conglomerates, 
  pink, 
  green, 
  buff, 
  brown 
  and 
  

   red 
  in 
  color, 
  with 
  glauconitic 
  coarse 
  sandstone 
  from 
  17 
  

   to 
  20 
  feet 
  above 
  the 
  base, 
  the 
  whole 
  110 
  feet 
  in 
  thickness. 
  

   No 
  fossils 
  being 
  found, 
  these 
  strata 
  are 
  tentatively 
  re- 
  

   ferred, 
  on 
  grounds 
  of 
  lithologic 
  similarity, 
  to 
  the 
  upper 
  

   Cambrian. 
  Ordovician 
  strata 
  follow, 
  with 
  lower 
  Ordovi- 
  

   cian 
  fossils 
  from 
  50 
  to 
  80 
  feet 
  above 
  the 
  base, 
  and 
  Rich- 
  

   mond 
  fossils 
  300 
  feet 
  above 
  the 
  base, 
  but 
  no 
  middle 
  

   Ordovician 
  fossils 
  were 
  found. 
  The 
  Ordovician 
  begins, 
  

   with 
  50 
  feet 
  of 
  calcareous 
  quartzitic 
  sandstone 
  and 
  is 
  

   overlain 
  by 
  gray 
  siliceous 
  cherty 
  limestone; 
  the 
  entire? 
  

   thickness 
  of 
  the 
  Ordovician 
  is 
  385 
  feet. 
  

  

  Lying 
  upon 
  the 
  Ordovician 
  are 
  50 
  feet 
  of 
  strata, 
  dark 
  

   gray 
  limestone 
  below 
  and 
  light 
  gray 
  saccharoidal-tex- 
  

   tured 
  crystalline 
  limestone 
  above, 
  referred 
  to 
  the 
  

   Niagaran. 
  

  

  Upper 
  Devonian, 
  with 
  Spirifer 
  wliitneyi, 
  follows 
  with 
  

   strata 
  of 
  black, 
  drab 
  and 
  gray 
  sandy 
  and 
  limy 
  fissile 
  shale 
  

   interbedded 
  with 
  nodular 
  and 
  concretionary 
  argillaceous 
  

   and 
  arenaceous 
  limestone, 
  locally 
  compact, 
  crystalline 
  

   and 
  cherty, 
  the 
  whole 
  being 
  80 
  feet 
  thick. 
  All 
  strata 
  

   below 
  the 
  Devonian 
  have 
  undergone 
  an 
  age 
  metamorph- 
  

   ism, 
  which 
  has 
  made 
  them 
  very 
  hard, 
  and 
  greatly 
  frac- 
  

   tured 
  them, 
  the 
  fissures 
  having 
  been 
  re-cemented 
  with 
  

   calcite 
  and 
  chert. 
  

  

  On 
  the 
  opposite 
  side 
  of 
  the 
  Tularosa 
  Basin, 
  in 
  the 
  

   southern 
  San 
  Andreas 
  Mountains, 
  substantially 
  the 
  same 
  

  

  Am. 
  Jour. 
  Sci.— 
  Fourth 
  Series, 
  Vol. 
  XLIX, 
  No. 
  290.— 
  February, 
  1920. 
  

  

  