﻿120 
  C. 
  L. 
  Baker 
  — 
  Contributions 
  to 
  the 
  

  

  les,, 
  Jemez 
  and 
  Nacimiento 
  mountains 
  of 
  southwestern 
  

   Rio 
  Arriba 
  County 
  and 
  central-northern 
  and 
  northeast- 
  

   ern 
  Sandoval 
  County. 
  

  

  Jurassic 
  (?). 
  — 
  Strata 
  lithologically 
  similar 
  to 
  the 
  Mor- 
  

   rison 
  of 
  regions 
  farther 
  north 
  overlie 
  the 
  upper 
  series 
  of 
  

   red 
  beds 
  on 
  the 
  flanks 
  of 
  the 
  Sangre 
  de 
  Cristo 
  and 
  Sandia 
  

   mountains. 
  It 
  is 
  probable, 
  from 
  the 
  facts 
  stated 
  in 
  the 
  

   preceding 
  paragraph, 
  that 
  an 
  epoch 
  of 
  erosion 
  followed 
  

   the 
  deposition 
  of 
  the 
  upper 
  red 
  beds. 
  

  

  The 
  strata 
  tentatively 
  referred 
  to 
  the 
  Morrison 
  are 
  

   light 
  to 
  dark 
  brownish-green 
  sandy 
  shales 
  and 
  sand- 
  

   stones. 
  The 
  sandstone 
  is 
  generally 
  stained 
  brown 
  with 
  

   limonite. 
  The 
  light 
  green 
  shales 
  contain 
  concretions 
  of 
  

   calcium 
  carbonate, 
  generally 
  coated 
  dark 
  reddish 
  brown 
  

   with 
  iron 
  oxide, 
  and 
  often 
  tuberous. 
  The 
  clay 
  weathers 
  

   like 
  a 
  joint 
  clay. 
  The 
  sand 
  beds 
  are 
  generally 
  nodular 
  

   and 
  not 
  persistent. 
  This 
  member 
  at 
  Las 
  Vegas 
  Hot 
  

   Springs 
  consists 
  of 
  heavy 
  bedded 
  brown 
  sandstone 
  inter- 
  

   bedded 
  with 
  green 
  sandy 
  shale 
  and 
  shaly 
  sandstone, 
  the 
  

   whole 
  totalling 
  250 
  feet 
  in 
  thickness. 
  These 
  strata 
  dis- 
  

   appear 
  to 
  the 
  eastward 
  in 
  the 
  High 
  Plains 
  region 
  between 
  

   Las 
  Vegas 
  and 
  Tucumcari. 
  

  

  Upper 
  Comanchean 
  (Tucumcari) 
  Beds. 
  — 
  The 
  follow- 
  

   ing 
  section 
  was 
  measured 
  on 
  Tucumcari 
  Mountain, 
  four 
  

   miles 
  south 
  of 
  the 
  town 
  of 
  Tucumcari: 
  

  

  Base. 
  Upper 
  Triassic. 
  

  

  1. 
  Purple-red 
  and 
  dark 
  brick-red 
  sandy 
  clay, 
  with 
  

  

  some 
  thin 
  gray 
  bands 
  and 
  blue-gray 
  to 
  green- 
  

   ish 
  irregular 
  bands 
  in 
  lower 
  portion. 
  Referred 
  

  

  to 
  the 
  Upper 
  Triassic 
  dz 
  100' 
  

  

  Upper 
  Comanchean 
  (Tucumcari 
  beds). 
  

  

  2. 
  Soft 
  cream-colored 
  sands, 
  unconsolidated 
  below 
  

  

  but 
  showing 
  stratification. 
  

  

  3. 
  Limonite-speckled, 
  thin-bedded, 
  gray-buff, 
  medi- 
  

  

  um-grained, 
  poorly 
  indurated 
  sandstone, 
  with 
  

   thin 
  beds 
  of 
  laminated 
  clayey 
  and 
  marly 
  light 
  

   blue-gray 
  sands 
  with 
  Gryphcea 
  tucumcarii 
  50 
  

   feet 
  below 
  the 
  top; 
  at 
  top, 
  contorted, 
  marly, 
  

   light 
  brown 
  sands 
  with 
  Turrit 
  ella 
  and 
  Car- 
  

   dium. 
  Total 
  thickness 
  of 
  (2) 
  and 
  (3) 
  325' 
  

  

  Unconformity. 
  

   Cretaceous. 
  

  

  4. 
  Dakota 
  sandstone, 
  buff, 
  cross-bedded, 
  ferruginous, 
  

  

  