﻿Stratigraphy 
  of 
  Eastern 
  New 
  Mexico. 
  123 
  

  

  grayish- 
  or 
  greenish-brown; 
  partially 
  quartzitic; 
  

   with 
  a 
  few 
  small-sized 
  pebbles; 
  very 
  ferruginous 
  

   on 
  bedding-planes; 
  contains 
  some 
  small 
  pellet 
  

   concretions 
  of 
  limonite; 
  fucoid 
  markings 
  abun- 
  

   dant. 
  This 
  is 
  certainly 
  a 
  tidal-flat 
  or 
  shore-line 
  

   deposit 
  and 
  is 
  thought 
  to 
  mark 
  the 
  beginning 
  of 
  

   Benton 
  deposition 
  ±3' 
  

  

  7. 
  Shale, 
  blue-black, 
  fissile 
  18' 
  

  

  8. 
  Sandstone, 
  dark 
  greenish 
  brown, 
  fucoidal 
  and 
  flaggy 
  0-5' 
  

  

  9. 
  Shale, 
  typical 
  Benton, 
  blue-black, 
  and 
  bituminous, 
  

  

  contains 
  an 
  occasional 
  thin 
  layer 
  of 
  sandstone 
  

   varying 
  in 
  thickness 
  from 
  a 
  fraction 
  of 
  an 
  inch 
  to 
  

   six 
  inches 
  45' 
  

  

  10. 
  Limestone, 
  brown, 
  filled 
  with 
  poorly 
  preserved 
  

  

  Inoceramus 
  labiatus 
  and 
  Ostrea 
  0-5' 
  

  

  11. 
  Shale, 
  typical 
  Benton, 
  with 
  two 
  thinly-laminated 
  

  

  sandstone 
  layers 
  each 
  about 
  two 
  inches 
  thick 
  in 
  

   lower 
  20 
  feet. 
  Shale 
  is 
  like 
  those 
  of 
  (9) 
  above, 
  

   and 
  also 
  contains 
  some 
  lenticular 
  concretions 
  of 
  

   clay 
  iron-stone, 
  in 
  places 
  changed 
  to 
  limonite 
  130' 
  

  

  12. 
  Limestone; 
  beds 
  of 
  brittle, 
  fine-grained, 
  blue-black 
  

  

  limestone, 
  containing 
  small, 
  often 
  pyritized 
  fossils 
  

   each 
  bed 
  about 
  a 
  foot 
  thick 
  alternating 
  with 
  thin, 
  

   slabby-bedded, 
  argillaceous 
  and 
  bituminous 
  dark 
  

   blue-black 
  limestone 
  80' 
  

  

  The 
  Mancos 
  formation 
  has 
  a 
  thickness 
  of 
  2950 
  feet 
  on 
  

   the 
  east 
  flanks 
  of 
  the 
  Sandia 
  Mountains 
  east 
  of 
  Algo- 
  

   dones. 
  It 
  rests 
  on 
  the 
  Dakota 
  and 
  consists 
  in 
  the 
  lower 
  

   part 
  of 
  dark 
  brown 
  bituminous 
  shales 
  with 
  thin 
  inter- 
  

   beds 
  of 
  limestone 
  carrying 
  Inoceramus 
  labiatus, 
  etc. 
  It 
  

   passes 
  upwards 
  into 
  beds 
  of 
  massive 
  gray 
  and 
  buff 
  sand- 
  

   stone 
  interbedded 
  with 
  carbonaceous 
  shale 
  and 
  coal 
  and 
  

   carries 
  Niobrara 
  fossils 
  in 
  the 
  upper 
  part. 
  Overlying 
  

   it 
  is 
  a 
  thick 
  assemblage 
  of 
  sandstones, 
  shales 
  and 
  coal 
  

   belonging 
  to 
  the 
  Mesa 
  Verde, 
  the 
  latter 
  being 
  overlain 
  by 
  

   orange-colored 
  Galisteo 
  sandstone 
  of 
  unknown 
  age 
  but 
  

   older 
  than 
  upper 
  Miocene. 
  

  

  A 
  remarkable 
  facies 
  of 
  the 
  Benton 
  rests 
  directly 
  upon 
  

   strata 
  of 
  the 
  Manzano 
  group 
  on 
  the 
  southwest 
  flanks 
  of 
  

   the 
  San 
  Andreas 
  Mountains 
  about 
  30 
  miles 
  north 
  of 
  the 
  

   Texas 
  line. 
  The 
  Benton 
  rests, 
  with 
  marked 
  erosional 
  

   unconformity 
  at 
  different 
  localities, 
  on 
  either 
  the 
  basal 
  

   San 
  Andreas 
  limestone 
  or 
  the 
  upper 
  beds 
  of 
  the 
  Yeso 
  

   formation. 
  The 
  base 
  of 
  the 
  Benton 
  consists 
  of 
  about 
  100 
  

   feet 
  of 
  grayish, 
  brownish, 
  and 
  reddish 
  concretionary 
  soft 
  

  

  