﻿Stratigraphy 
  of 
  Eastern 
  New 
  Mexico. 
  121 
  

  

  locally 
  qnartzitic 
  and 
  conglomeratic; 
  ripple- 
  

   marked 
  ± 
  100' 
  

  

  Unconformity. 
  

   Cenozoic. 
  

  

  5. 
  Caliche, 
  cream-colored, 
  cementing 
  sands 
  and 
  

  

  gravel 
  10' 
  

  

  A 
  small 
  section 
  exposed 
  in 
  a 
  bluff 
  on 
  the 
  north 
  side 
  of 
  

   a 
  small 
  arroyo 
  11% 
  miles 
  west 
  of 
  Tucumcari 
  on 
  the 
  

   Montoya 
  road 
  yielded 
  more 
  definite 
  evidence 
  of 
  the 
  age 
  

   of 
  the 
  Tucumcari 
  beds. 
  Here 
  tawny 
  yellow 
  nodular 
  very 
  

   sandy 
  marls 
  have 
  an 
  exposed 
  thickness 
  of 
  30 
  feet 
  and 
  

   are 
  directly 
  overlain 
  by 
  Dakota. 
  At 
  the 
  base 
  is 
  a 
  zone 
  

   filled 
  with 
  Gryphcea 
  tucumcarii, 
  some 
  of 
  which 
  are 
  of 
  

   very 
  large 
  size. 
  Twenty 
  five 
  feet 
  higher 
  and 
  five 
  feet 
  

   beneath 
  the 
  Dakota 
  is 
  a 
  zone 
  with 
  Ostrea 
  quadriplicata, 
  

   Turritella 
  and 
  Cardium. 
  Ostrea 
  quadriplicata 
  is 
  con- 
  

   fined 
  to 
  the 
  strata 
  between 
  the 
  Quarry 
  and 
  Mainstreet 
  

   limestones 
  of 
  the 
  Denison 
  section 
  of 
  north 
  Texas, 
  the 
  age 
  

   of 
  which 
  is 
  middle 
  or 
  upper 
  Cenomanian. 
  

  

  Sandstones 
  and 
  sands 
  lithologically 
  similar 
  to 
  and 
  

   occupying 
  the 
  same 
  stratigraphic 
  position 
  as 
  the 
  Tucum- 
  

   cari 
  beds 
  are 
  found 
  as 
  far 
  west 
  as 
  the 
  southeastern 
  flanks 
  

   of 
  the 
  Sangre 
  de 
  Cristo 
  Mountains. 
  Their 
  southern 
  

   limit 
  is 
  found 
  in 
  the 
  high 
  mesas 
  eastwards 
  from 
  south 
  of 
  

   Las 
  Vegas 
  and 
  their 
  southwestern 
  limit 
  is 
  found 
  two 
  or 
  

   three 
  miles 
  west 
  of 
  the 
  northwesternmost 
  point 
  of 
  the 
  

   Llano 
  Estacado. 
  

  

  Cretaceous. 
  — 
  The 
  Dakota 
  sandstone 
  has 
  its 
  southern 
  

   limit 
  in 
  the 
  region 
  of 
  the 
  Sierra 
  Blanca 
  group 
  of 
  intru- 
  

   sives 
  in 
  west-central 
  Lincoln 
  County. 
  It 
  is 
  widely 
  dis- 
  

   tributed 
  in 
  the 
  region 
  north 
  of 
  the 
  35th 
  Parallel, 
  where 
  

   it 
  outcrops 
  in 
  the 
  flanks 
  of 
  the 
  mountain 
  ranges 
  and 
  out- 
  

   crops 
  in 
  or 
  underlies 
  the 
  High 
  Plains 
  of 
  northeastern 
  

   New 
  Mexico. 
  It 
  is 
  everywhere 
  very 
  distinctive, 
  possess- 
  

   ing 
  the 
  same 
  lithologic 
  characteristics. 
  A 
  description 
  of 
  

   the 
  strata 
  in 
  the 
  hogbacks 
  along 
  the 
  east 
  flank 
  of 
  the 
  

   Front 
  Range 
  of 
  the 
  southernmost 
  Rockies 
  will 
  suffice 
  for 
  

   the 
  entire 
  province 
  of 
  the 
  Dakota 
  in 
  New 
  Mexico. 
  The 
  

   section 
  in 
  the 
  water 
  gap 
  of 
  Gallinas 
  Creek 
  east 
  of 
  Las 
  

   Vegas 
  Hot 
  Springs 
  follows 
  : 
  

  

  