﻿324 
  W. 
  T. 
  Lee 
  — 
  Notes 
  on 
  the 
  Manzano 
  Group. 
  

  

  As 
  none 
  of 
  these 
  are 
  mentioned 
  in 
  either 
  of 
  the 
  papers 
  

   reviewed 
  it 
  would 
  be 
  difficult 
  for 
  one 
  not 
  familiar 
  with 
  

   the 
  formations 
  described 
  to 
  compare 
  the 
  results 
  of 
  the 
  

   several 
  observers. 
  As 
  there 
  are 
  many 
  who 
  will 
  desire 
  

   to 
  use 
  all 
  the 
  results 
  obtainable 
  in 
  this 
  interesting 
  region 
  

   it 
  seems 
  desirable 
  to 
  call 
  attention 
  to 
  observations 
  made 
  

   by 
  other 
  men 
  on 
  the 
  formations 
  described 
  in 
  the 
  papers 
  

   reviewed. 
  Baker's 
  paper 
  touches 
  several 
  unsettled 
  

   questions 
  but 
  I 
  shall 
  review 
  only 
  those 
  which 
  I 
  am 
  per- 
  

   sonally 
  somewhat 
  familiar 
  with. 
  These 
  are 
  : 
  The 
  Penn- 
  

   sylvanian-Permian 
  boundary; 
  the 
  age 
  of 
  the 
  Manzano 
  

   group; 
  the 
  nature 
  of 
  the 
  Upper 
  Triassic 
  deposits 
  and 
  

   the 
  correlation 
  of 
  Shinarump 
  conglomerate 
  with 
  the 
  

   Glorieta 
  sandstone 
  of 
  Baker; 
  the 
  Triassic- 
  Jurassic 
  

   boundary; 
  and, 
  the 
  age 
  of 
  certain 
  sedimentary 
  rocks 
  

   which 
  are 
  described 
  by 
  Baker 
  as 
  Upper 
  Triassic. 
  

  

  These 
  papers 
  emphasize 
  the 
  separation 
  of 
  the 
  Man- 
  

   zano 
  group 
  from 
  the 
  underlying 
  rocks 
  by 
  an 
  unconform- 
  

   ity, 
  the 
  significance 
  of 
  which 
  has 
  been 
  steadily 
  increasing 
  

   since 
  it 
  was 
  first 
  described 
  in 
  1909. 
  2 
  During 
  the 
  years 
  

   immediately 
  following 
  this 
  description 
  the 
  unconformity 
  

   was 
  observed 
  in 
  many 
  places 
  and 
  came 
  soon 
  to 
  be 
  

   generally 
  regarded 
  as 
  an 
  unconformity 
  of 
  wide 
  extent, 
  

   which 
  appropriately 
  marks 
  the 
  separation 
  of 
  the 
  Penn- 
  

   sylvanian 
  from 
  the 
  Permian 
  series. 
  3 
  But 
  in 
  the 
  press 
  of 
  

   other 
  matters 
  the 
  details 
  were 
  not 
  published. 
  

  

  Baker 
  refers 
  to 
  the 
  pre-Abo 
  disturbance 
  as 
  causing 
  

   "gentle 
  folding 
  in 
  the 
  regions 
  of 
  all 
  present 
  mountain 
  

   uplifts" 
  but 
  states 
  that 
  east 
  of 
  the 
  front 
  range 
  near 
  

   Mora 
  the 
  Abo 
  formation 
  contains 
  "several 
  thousand 
  

   feet 
  of 
  arkoses." 
  It 
  was 
  this 
  movement 
  that 
  produced 
  

   the 
  highlands 
  which 
  I 
  have 
  called 
  the 
  Ancestral 
  Rocky 
  

   Mountains 
  4 
  and 
  which 
  furnished 
  not 
  only 
  the 
  thousands 
  

   of 
  feet 
  of 
  arkoses 
  observed 
  near 
  Mora 
  but 
  the 
  coarse 
  red 
  

   conglomerates 
  of 
  Permian 
  and 
  perhaps 
  in 
  part 
  of 
  Tri- 
  

   assic 
  age 
  many 
  thousands 
  of 
  feet 
  thick 
  in 
  northern 
  New 
  

   Mexico 
  and 
  southern 
  Colorado. 
  5 
  No 
  close 
  correlation 
  of 
  

  

  2 
  Lee, 
  Willis 
  T., 
  and 
  Girty, 
  George 
  H. 
  : 
  The 
  Manzano 
  group 
  of 
  the 
  Eio 
  

   Grand 
  Valley, 
  New 
  Mexico, 
  U. 
  S. 
  Geol. 
  Survey, 
  Bull. 
  389, 
  1909. 
  

  

  3 
  Lee, 
  Willis 
  T. 
  : 
  General 
  stratigraphie 
  break 
  "between 
  Pennsylvanian 
  and 
  

   Permian 
  in 
  western 
  America, 
  Bull. 
  Geol. 
  Soc. 
  America, 
  vol. 
  28, 
  pp. 
  169- 
  

   170, 
  1917. 
  

  

  4 
  Lee, 
  Willis 
  T. 
  : 
  Early 
  Mesozoic 
  physiography 
  of 
  the 
  southern 
  Rocky 
  

   Mountains, 
  Smithsonian 
  Misc. 
  Collection, 
  vol. 
  69, 
  No. 
  4, 
  1918. 
  

  

  5 
  Lee, 
  Willis 
  T., 
  and 
  Knowlton, 
  F. 
  H. 
  : 
  Geology 
  and 
  paleontology 
  of 
  the 
  

   Eaton 
  Mesa 
  and 
  other 
  regions 
  in 
  Colorado 
  and 
  New 
  Mexico, 
  U. 
  S. 
  Geol. 
  

   Survey, 
  Prof. 
  Paper 
  101, 
  p. 
  41, 
  1917. 
  

  

  