﻿262 
  

  

  G. 
  R. 
  Wieland 
  — 
  On 
  Liassic 
  Floras. 
  

  

  such 
  widely 
  separated 
  florae 
  as 
  those 
  cited 
  are 
  doubtless 
  further 
  

   obscured 
  by 
  the 
  fact 
  that 
  any 
  given 
  flora 
  may 
  be 
  old 
  or 
  young 
  

   for 
  the 
  region 
  in 
  which 
  it 
  occurs. 
  A 
  plant 
  facies 
  may 
  be 
  

   either 
  juvenile 
  or 
  senile. 
  Thus, 
  as 
  will 
  be 
  further 
  cited 
  below, 
  

   it 
  is 
  strongly 
  suspected 
  that 
  the 
  plants 
  of 
  the 
  Inferior 
  Oolite 
  

   of 
  the 
  Yorkshire 
  Coast 
  are 
  old, 
  are 
  really 
  a 
  left-over 
  Liassic 
  

  

  Fig. 
  2. 
  

  

  Fig. 
  2. 
  Principal 
  Triassic 
  and 
  Jurassic 
  plant 
  localities 
  of 
  Western 
  Europe 
  

   and 
  the 
  extra-arctic 
  Americas. 
  [Disks] 
  denote 
  early, 
  and 
  circles 
  later 
  Trias, 
  

   solid 
  black 
  stars, 
  early, 
  and 
  outline 
  stars 
  later 
  Jura. 
  The 
  arrow 
  points 
  out 
  

   the 
  newly 
  discovered 
  Mixteca 
  Alta 
  horizons 
  of 
  Mexico, 
  where 
  600 
  meters 
  of 
  

   Liassic 
  strata 
  have 
  been 
  measured 
  and 
  true 
  Triassic 
  plants 
  are 
  also 
  believed 
  

   to 
  occur. 
  These 
  plant 
  beds 
  are 
  widely 
  extended 
  over 
  the 
  region 
  stretching 
  

   westwardly 
  from 
  the 
  valley 
  of 
  the 
  Nochixtlan 
  river 
  in 
  Oaxaca 
  to 
  Tlapa 
  in 
  

   the 
  state 
  of 
  Guerrero 
  (or 
  further), 
  and 
  northwardly 
  into 
  southern 
  Puebla. 
  

  

  rather 
  than 
  a 
  typical 
  mid- 
  Jurassic 
  facies. 
  For 
  these 
  plants 
  

   may 
  readily 
  have 
  been 
  existent 
  during 
  the 
  deposition 
  of 
  the 
  

  

  