﻿272 
  

  

  G. 
  R. 
  Wieland 
  — 
  On 
  Liassic 
  Floras. 
  

  

  Table 
  IVc. 
  — 
  Inferior 
  Oolite 
  of 
  Yorkshire 
  Coast. 
  

  

  Ferns 
  _ 
  20 
  species 
  = 
  37; 
  

  

  Cycadophytans 
  23 
  " 
  = 
  42 
  

  

  Conifers 
  and 
  Ginkgos 
  9 
  " 
  = 
  17 
  

  

  Equisetums 
  _ 
  __ 
  2 
  " 
  = 
  4 
  

  

  54 
  species 
  

  

  Table 
  V. 
  — 
  Elements 
  of 
  Typical 
  Rhatic 
  — 
  Oolitic 
  Florce. 
  

  

  

  1 
  2 
  

  

  

  

  

  CO 
  

  

  a 
  

  

  

  

  

  %'s 
  

  

  l-l 
  

  

  3 
  Q> 
  

  

  shire 
  

   rior 
  

  

  Lite 
  

  

  r— 
  ( 
  

  

  O 
  03 
  

  

  r£3 
  03 
  

  

  r-H 
  0D 
  

  

  fi 
  o 
  

  

  rt.g 
  

  

  oo 
  

  

  

  42 
  

  

  o 
  -o 
  

   46 
  

  

  

  S3 
  

  

  O 
  

  

  3 
  

  

  Oaxa 
  

   Lias 
  

   Ehati 
  

  

  ^3 
  

  

  3 
  

  

  Ferns 
  

  

  37 
  

  

  35 
  

  

  32 
  

  

  18 
  

  

  48 
  

  

  37 
  

  

  Cycadeans 
  

  

  28 
  

  

  38 
  

  

  43 
  

  

  33 
  + 
  

  

  34 
  + 
  

  

  70 
  

  

  33 
  

  

  40 
  

  

  Conifers 
  __ 
  

  

  27 
  

  

  12 
  

  

  (,. 
  

  

  17 
  

  

  8 
  

  

  (2) 
  

  

  9 
  

  

  13 
  

  

  Ginkgos 
  __ 
  

  

  

  4 
  

  

  9 
  

  

  ? 
  

  

  

  2 
  

  

  2± 
  

  

  Cordaites 
  _ 
  

  

  

  

  

  9 
  

  

  9 
  

  

  9 
  

  

  8 
  

  

  2 
  

  

  2 
  + 
  

  

  Equisetums 
  

  

  2 
  

  

  ? 
  

  

  4 
  

  

  5 
  

  

  2 
  

  

  2 
  

  

  5-5 
  

  

  3 
  

  

  Before 
  passing 
  the 
  comparisons 
  afforded 
  by 
  the 
  preceding 
  

   tables, 
  it 
  may 
  be 
  mentioned 
  that 
  they 
  show 
  still 
  more 
  clearly 
  

   the 
  general 
  course 
  of 
  change 
  from 
  Rhatic 
  to 
  mid- 
  Jurassic 
  

   times 
  when 
  necessary 
  modifications 
  are 
  borne 
  in 
  mind. 
  Thus 
  

   the 
  percentage 
  of 
  cycads 
  in 
  the 
  Bornholm 
  flora 
  is 
  relatively 
  

   lower, 
  because 
  not 
  augmented 
  by 
  fruits 
  ; 
  while 
  the 
  Yorkshire 
  

   Coast 
  cycad 
  percentage 
  would 
  also 
  be 
  higher 
  were 
  the 
  fruits 
  

   more 
  recently 
  discovered 
  by 
  JSTathorst 
  included. 
  In 
  general 
  

   there 
  is, 
  indeed, 
  much 
  of 
  consonance 
  in 
  these 
  figures, 
  and 
  it 
  

   will 
  certainly 
  be 
  of 
  interest, 
  as 
  the 
  species 
  are 
  from 
  year 
  to 
  

   year 
  augmented 
  and 
  revised, 
  to 
  make 
  the 
  necessary 
  corrections 
  

   as 
  well 
  as 
  to 
  add 
  the 
  statistics 
  of 
  other 
  regions. 
  Having 
  

   brought 
  to 
  view 
  the 
  general 
  composition 
  of 
  the 
  Mixteca 
  Alta 
  

   flora 
  and 
  made 
  clear 
  the 
  fact 
  that 
  it 
  contains 
  a 
  relatively 
  more 
  

   numerous 
  cycad 
  element 
  than 
  any 
  other, 
  we 
  pass 
  on 
  to 
  a 
  

   further 
  consideration 
  of 
  the 
  indicated 
  ao;e. 
  

  

  (c) 
  Age 
  of 
  the 
  Plant 
  Beds 
  of 
  the 
  Section 
  Consuelo. 
  

  

  In 
  order 
  to 
  throw 
  into 
  strong 
  contrast 
  the 
  course 
  of 
  change 
  

   in 
  early 
  to 
  mid-Mesozoic 
  forest 
  components 
  and 
  further 
  illus- 
  

  

  