﻿Richardson 
  — 
  Note 
  on 
  the 
  Age 
  of 
  the 
  Scranton 
  Coal. 
  243 
  

  

  Art. 
  XXII. 
  — 
  Note 
  on 
  the 
  Age 
  of 
  the 
  Scranton 
  Coal, 
  Denver 
  

   Basin, 
  Colorado 
  ;* 
  by 
  (x. 
  B. 
  Richardson. 
  

  

  In 
  the 
  course 
  of 
  a 
  reconnaissance 
  in 
  the 
  Denver 
  Basin, 
  Colo- 
  

   rado, 
  in 
  1910-11, 
  1 
  traced, 
  over 
  a 
  considerable 
  area 
  on 
  the 
  plains 
  

   east 
  of 
  Castle 
  Bock, 
  a 
  zone 
  of 
  coal 
  beds 
  carrying 
  fossil 
  leaves 
  

   which 
  Knowlton 
  considers 
  to 
  be 
  of 
  post-Laramie 
  age. 
  On 
  

   stratigraphic 
  evidence 
  I 
  correlated 
  this 
  coal 
  zone 
  with 
  the 
  

   Scranton 
  coals, 
  which 
  a 
  number 
  of 
  years 
  ago 
  were 
  mined 
  in 
  a 
  

   shaft 
  20 
  miles 
  east 
  of 
  Denver, 
  and 
  which, 
  ever 
  since 
  the 
  publi- 
  

   cation 
  of 
  the 
  Monograph 
  on 
  the 
  Denver 
  Basin, 
  r 
  in 
  1896, 
  have 
  

   been 
  referred 
  to 
  the 
  Laramie 
  formation. 
  This 
  discrepancy 
  in 
  

   age 
  assignment 
  prompted 
  the 
  desire 
  that 
  more 
  field 
  work 
  be 
  

   done 
  before 
  publication 
  of 
  the 
  results, 
  but 
  the 
  opportunity 
  not 
  

   having 
  arisen 
  it 
  seems 
  desirable, 
  considering 
  that 
  the 
  Denver 
  

   Basin 
  is 
  the 
  type 
  area 
  of 
  the 
  much-discussed 
  Laramie 
  forma- 
  

   tion, 
  to 
  publish 
  the 
  evidence 
  now. 
  

  

  The 
  coal 
  zone 
  referred 
  to 
  occurs 
  between 
  900 
  and 
  1200 
  feet 
  

   above 
  the 
  base 
  of 
  the 
  Laramie 
  formation. 
  It 
  crops 
  out 
  over 
  a 
  

   considerable 
  area 
  and 
  has 
  been 
  prospected 
  in 
  a 
  number 
  of 
  

   places, 
  especially 
  in 
  the 
  vicinity 
  of 
  Calhan 
  and 
  Fondis. 
  Only 
  

   here 
  and 
  there 
  the 
  coal 
  is 
  pure 
  enough 
  to 
  warrant 
  opening 
  

   country 
  banks, 
  such 
  as 
  the 
  Purdon 
  mine 
  in 
  sec. 
  27, 
  T. 
  11 
  S., 
  

   K. 
  61 
  W., 
  and 
  the 
  Moseby 
  mine 
  in 
  sec. 
  18, 
  T. 
  13 
  S., 
  R. 
  62 
  W. 
  

   The 
  coal 
  is 
  a 
  low 
  grade 
  sub-bituminous 
  variety. 
  I 
  have 
  traced 
  

   this 
  coal 
  zone 
  to 
  within 
  15 
  miles 
  of 
  Scranton, 
  in 
  sec. 
  16, 
  T. 
  3 
  S., 
  

   R. 
  65 
  W., 
  and 
  although 
  actual 
  connection 
  with 
  the 
  Scranton 
  

   coals 
  by 
  following 
  the 
  outcrop 
  is 
  impossible, 
  because 
  of 
  the 
  

   cover 
  of 
  later 
  deposits, 
  it 
  is 
  evident 
  from 
  the 
  field 
  relations 
  

   that 
  the 
  Scranton 
  beds 
  are 
  in 
  the 
  zone 
  traced. 
  

  

  The 
  following 
  list 
  of 
  fossil 
  leaves 
  from 
  this 
  coal 
  zone 
  were 
  

   collected 
  by 
  the 
  writer 
  and 
  C. 
  W. 
  Cooke 
  in 
  1910 
  at 
  the 
  locali- 
  

   ties 
  mentioned 
  : 
  Sec. 
  30, 
  T. 
  9 
  S., 
  R. 
  60 
  W.; 
  sees. 
  7 
  and 
  33, 
  T. 
  

   9 
  S., 
  R. 
  61 
  W.; 
  sec. 
  27, 
  T. 
  11 
  S., 
  R. 
  61 
  W.; 
  sec. 
  18, 
  T. 
  13 
  S., 
  

   R. 
  61 
  W. 
  

  

  List 
  of 
  fossil 
  leaves 
  from 
  upper 
  coal 
  zone, 
  Denver 
  Basin 
  ; 
  

   by 
  F. 
  H. 
  Knowlton. 
  

  

  Pteris 
  undulata 
  Lx. 
  

   Ficus 
  spectabilis 
  Lx. 
  

   Laurus 
  socialis 
  Lx. 
  

   Platanus 
  Haydenii 
  Newb. 
  

  

  * 
  Published 
  by 
  permission 
  of 
  the 
  Director, 
  U. 
  S. 
  Geological 
  Survey, 
  

   f 
  Emmons, 
  S. 
  F., 
  Cross, 
  Whitman, 
  and 
  Eldridge, 
  G, 
  H., 
  Geology 
  of 
  the 
  

   Denver 
  Basin 
  in 
  Colorado, 
  U. 
  S. 
  Geol. 
  Survey 
  Mon. 
  27, 
  pp. 
  373-375, 
  1896. 
  

  

  