﻿84 
  EEPORT 
  UNITED 
  STATES 
  GEOLOGICAL 
  SURVEY. 
  

  

  Trias 
  to 
  the 
  surface. 
  At 
  the 
  sources 
  of 
  the 
  Uncompahgre 
  and 
  San 
  

   Miguel 
  Elvers 
  there 
  are 
  outcrops 
  of 
  red 
  beds, 
  probably 
  Carboniferous 
  

   in 
  part. 
  

  

  I 
  have 
  adhered 
  to 
  the 
  name 
  Triassic, 
  for 
  the 
  series 
  just 
  described, 
  

   because 
  the 
  evidence 
  is 
  conflicting, 
  and 
  the 
  beds 
  are 
  usually 
  called 
  

   Triassic 
  as 
  a 
  provisional 
  name. 
  In 
  New 
  Mexico, 
  Cope 
  has 
  found 
  fossils 
  

   that 
  he 
  says 
  are 
  favorable 
  to 
  the 
  identification 
  of 
  this 
  horizon 
  with 
  the 
  

   Trias.* 
  These 
  fossils 
  are 
  remains 
  of 
  a 
  new 
  genus 
  TypotJwrax 
  coccinarum. 
  

   He 
  also 
  obtained, 
  from 
  the 
  same 
  horizon, 
  other 
  vertebrate 
  remains, 
  and 
  

   a 
  new 
  species 
  of 
  Unio, 
  the 
  latter 
  showing 
  that 
  at 
  least 
  a 
  portion 
  of 
  the 
  

   Trias 
  of 
  the 
  West 
  is 
  of 
  fresh- 
  water 
  origin. 
  

  

  Kear 
  the 
  Abajo 
  Mountains 
  Dr. 
  Newberry 
  found 
  saurian 
  bones 
  and 
  

   silicified 
  wood 
  in 
  shales 
  just 
  above 
  the 
  massive 
  yellow 
  and 
  red 
  calcareous 
  

   sandstones 
  that 
  form 
  the 
  top 
  of 
  his 
  Triassic 
  series 
  in 
  the 
  section 
  I 
  have 
  

   already 
  quoted. 
  These 
  bones 
  were 
  associated 
  with 
  fossil 
  shells 
  resem- 
  

   bling 
  Natica.] 
  

  

  At 
  the 
  Gohre 
  or 
  old 
  copper-mines 
  of 
  Abiquiu 
  he 
  found 
  fossil 
  plants, 
  

   of 
  which 
  he 
  says 
  : 
  

  

  We 
  have, 
  therefore, 
  in 
  these 
  plants 
  evidence 
  of 
  the 
  Triassic 
  age 
  of 
  all 
  the 
  variegated 
  gyp- 
  

   siferous 
  rocks 
  of 
  Northern 
  New 
  Mexico 
  ; 
  for 
  the 
  Lower 
  Cretaceons 
  sandstones 
  immediately 
  

   overlie 
  the 
  plant-bed 
  of 
  the 
  Cobre4 
  

  

  In 
  Utah, 
  Mr. 
  E. 
  E. 
  Howell 
  obtained 
  fossils 
  from 
  the 
  base 
  of 
  the 
  Trias. 
  

   Dr. 
  C. 
  A. 
  White 
  describes 
  these,§ 
  and 
  says: 
  

  

  If 
  the 
  collections 
  had 
  been 
  placed 
  in 
  my 
  hands 
  for 
  determiiiation, 
  without 
  any 
  statement 
  

   of 
  their 
  stratigraphical 
  position, 
  I 
  should 
  have 
  referred 
  them 
  to 
  the 
  Jurassic 
  period, 
  with 
  

   no 
  other 
  doubts 
  than 
  those 
  suggested 
  by 
  the 
  imperfection 
  of 
  the 
  specimens. 
  

  

  In 
  the 
  Black 
  Hills, 
  Dr. 
  Hayden 
  also 
  found 
  Jurassic 
  fossils 
  near 
  the 
  

   base 
  of 
  the 
  Triassic. 
  || 
  

  

  The 
  plants 
  that 
  Dr. 
  Newberry 
  refers 
  to 
  the 
  Triassic 
  were 
  immediately 
  

   beneath 
  the 
  sandstones 
  of 
  the 
  Dakota 
  group. 
  While 
  in 
  Utah, 
  Howell 
  

   found 
  Jurassic 
  fossils 
  in 
  nearly 
  the 
  same 
  position. 
  That 
  the 
  beds 
  are 
  

   near 
  the 
  same 
  horizon 
  I 
  will 
  attempt 
  to 
  show 
  farther 
  on. 
  In 
  New 
  Mexico, 
  

   Mr. 
  Gilbert 
  is 
  inclined 
  to 
  think 
  that 
  the 
  Jura 
  is 
  absent. 
  The 
  summit 
  of 
  

   his 
  Trias 
  corresponds 
  with 
  that 
  of 
  Powell, 
  Newberry, 
  Howell, 
  and 
  mine, 
  

   in 
  Colorado. 
  Above 
  the 
  Trias 
  he 
  has 
  a 
  series 
  of 
  sandstones 
  and 
  shales 
  

   which 
  he 
  refers 
  to 
  the 
  lower 
  part 
  of 
  the 
  Cretaceous. 
  These 
  beds 
  agree 
  

   with 
  the 
  descriptions 
  of 
  tihose 
  usually 
  referred 
  to, 
  the 
  Jurassic, 
  with, 
  

   perhaps, 
  the 
  exception 
  of 
  the 
  gypsum, 
  which 
  appears 
  to 
  be 
  absent 
  in 
  

   Gilbert's 
  section. 
  In 
  some 
  parts 
  of 
  Colorado 
  the 
  beds 
  below 
  the 
  Dakota 
  

   group 
  are 
  destitute 
  of 
  gypsum 
  to 
  the 
  top 
  of 
  the 
  red 
  sandstones. 
  From 
  

   what 
  I 
  have 
  written, 
  it 
  appears 
  that 
  the 
  evidence 
  supplied 
  by 
  vegetable 
  

   paleontology 
  is 
  opposed 
  to 
  that 
  derived 
  from 
  the 
  animal 
  remains. 
  This 
  

   is 
  also 
  the 
  case 
  in 
  Eastern 
  North 
  America, 
  where 
  the 
  Triassic 
  may 
  

   eventually 
  prove 
  to 
  be 
  Jurassic. 
  

  

  The 
  following 
  sections 
  include 
  also 
  the 
  Jurassic 
  strata: 
  

  

  *Eeport 
  of 
  the 
  Chief 
  of 
  Engineers, 
  p. 
  981. 
  

  

  t 
  Exploring 
  Expedition 
  to 
  Junction 
  of 
  Grand 
  and 
  Green 
  Eivers, 
  pp. 
  91, 
  92. 
  

   X 
  Exploring 
  Expedition 
  to 
  Junction 
  of 
  Grand 
  and 
  Green 
  Rivers, 
  pp. 
  68, 
  69. 
  

   $ 
  Geology 
  of 
  Eastern 
  Portion 
  of 
  the 
  Uinta 
  Mountains, 
  p. 
  81. 
  

  

  II 
  Geological 
  Report 
  of 
  the 
  Exploration 
  of 
  the 
  Yellowstone 
  and 
  Missouri 
  Rivers, 
  1 
  859-' 
  60, 
  

   p. 
  II. 
  

  

  