﻿330 
  MK. 
  A. 
  C. 
  SEWARD 
  ON 
  THE 
  ASSOCIATION 
  OF 
  [Aug. 
  1 
  89 
  7, 
  

  

  with, 
  the 
  leaf-scars 
  is 
  partially 
  overlain 
  by 
  a 
  comparatively 
  thick 
  

   layer 
  of 
  sandstone, 
  which 
  is 
  marked 
  by 
  numerous 
  line 
  longitudinal 
  and 
  

   transverse 
  lines. 
  This 
  is 
  no 
  doubt 
  the 
  cast 
  of 
  some 
  deeper-lying 
  

   tissues, 
  either 
  the 
  wood 
  or 
  the 
  regularly-disposed 
  tissue 
  of 
  the 
  outer 
  

   cortex. 
  

  

  In 
  text-fig. 
  3 
  (p. 
  329) 
  a 
  small 
  piece 
  of 
  a 
  stem 
  is 
  shown 
  in 
  which 
  the 
  

   leaf-scars 
  are 
  clearly 
  seen 
  at 
  A 
  ; 
  at 
  B 
  the 
  cast 
  presents 
  a 
  Knorria- 
  

   like 
  appearance 
  : 
  the 
  somewhat 
  irregular 
  elongated 
  projections 
  no 
  

   doubt 
  represent 
  the 
  casts 
  of 
  elliptical 
  spaces, 
  left 
  in 
  the 
  cortical 
  

   tissue 
  of 
  the 
  stem 
  after 
  the 
  decay 
  of 
  the 
  delicate 
  tissue 
  accompanying 
  

   the 
  outgoing 
  leaf-bundles. 
  

  

  Turning 
  to 
  PI. 
  XXII. 
  fig. 
  3, 
  we 
  have 
  a 
  very 
  imperfect 
  cast 
  of 
  a 
  

   stem 
  with 
  smaller 
  leaf-scars, 
  and, 
  as 
  in 
  the 
  larger 
  specimens, 
  without 
  

   any 
  leaf-cushions. 
  It 
  is 
  impossible 
  to 
  attempt 
  an 
  exact 
  specific 
  

   identification 
  of 
  so 
  indistinct 
  a 
  cast, 
  but 
  it 
  is 
  probably 
  a 
  smaller 
  form 
  

   of 
  Sigillaria 
  Brardi, 
  or 
  at 
  least 
  it 
  may 
  be 
  referred 
  to 
  that 
  species. 
  

   It 
  bears 
  a 
  fairly 
  close 
  resemblance 
  to 
  a 
  specimen 
  which 
  Grand' 
  Eury 
  

   has 
  described 
  from 
  the 
  Gard 
  as 
  an 
  example 
  of 
  Sigillaria 
  Grasiana, 
  

   Brongn. 
  1 
  

  

  ' 
  ? 
  Sigillaria 
  sp. 
  

  

  (PI. 
  XXII. 
  fig. 
  4 
  a 
  & 
  PI. 
  XXIV. 
  fig. 
  3 
  ; 
  text-fig. 
  2/, 
  p. 
  327.) 
  

  

  In 
  PI. 
  XXII. 
  fig. 
  4 
  a 
  there 
  is 
  a 
  fairly 
  well-marked 
  impression, 
  

   reduced 
  about 
  one-half 
  in 
  size, 
  of 
  a 
  stem-surface 
  covered 
  with 
  leaf- 
  

   cushions 
  which 
  in 
  a 
  few 
  places 
  show 
  the 
  outlines 
  of 
  a 
  leaf-scar. 
  Part 
  

   of 
  the 
  same 
  specimen 
  is 
  shown 
  nearly 
  natural 
  size 
  in 
  PI. 
  XXIV. 
  fig. 
  3. 
  

  

  In 
  text-fig. 
  2/ 
  (p. 
  327) 
  one 
  of 
  the 
  best 
  leaf-cushions 
  is 
  drawn 
  on 
  a 
  

   larger 
  scale, 
  showing 
  the 
  leaf 
  -scar 
  s. 
  The 
  preservation 
  is 
  too 
  imperfect 
  

   to 
  allow 
  of 
  a 
  more 
  detailed 
  description,' 
  and 
  one 
  cannot 
  feel 
  quite 
  

   certain 
  as 
  to 
  the 
  true 
  affinities 
  of 
  the 
  stem. 
  The 
  cushion 
  shown 
  in 
  

   fig. 
  2/ 
  has 
  a 
  breadth 
  of 
  7 
  mm. 
  In 
  certain 
  forms 
  of 
  stems 
  it 
  is 
  not 
  

   an 
  easy 
  matter, 
  indeed 
  in 
  badly 
  -preserved 
  specimens 
  it 
  is 
  an 
  impossi- 
  

   bility, 
  to 
  distinguish 
  between 
  Sigillaria 
  and 
  Lepidodendron. 
  In 
  the 
  

   specimen 
  shown 
  in 
  PI. 
  XXII. 
  fig. 
  4 
  a, 
  the 
  outlines 
  of 
  the 
  leaf-cushions 
  

   are 
  fairly 
  distinct, 
  but 
  it 
  is 
  only 
  in 
  a 
  few 
  places 
  that 
  the 
  leaf- 
  scars 
  

   can 
  be 
  made 
  out; 
  the 
  more 
  minute 
  surface-features 
  cannot 
  be 
  seen. 
  

   There 
  is 
  a 
  certain 
  amount 
  of 
  resemblance 
  between 
  this 
  impression 
  

   from 
  Vereeniging 
  and 
  those 
  of 
  Lepidodendron 
  Pedroanum 
  (Carr.) 
  

   from 
  Brazil, 
  2 
  but 
  it 
  would 
  be 
  unwise 
  to 
  press 
  the 
  agreement 
  too 
  far. 
  

   The 
  slightly 
  enlarged 
  drawing 
  in 
  fig. 
  2/ 
  shows 
  the 
  leaf-scar 
  to 
  be 
  

   much 
  smaller 
  than 
  that 
  of 
  Sigillaria 
  Brardi 
  (PL 
  XXIII. 
  fig. 
  2) 
  ; 
  the 
  

   leaf-cushion,on 
  the 
  other 
  hand, 
  is 
  much 
  larger. 
  This 
  difference 
  in 
  the 
  

   size 
  of 
  the 
  leaf-cushion 
  is, 
  however, 
  not 
  a 
  character 
  of 
  essential 
  impor- 
  

   tance 
  as 
  regards 
  a 
  comparison 
  w 
  r 
  ith 
  S. 
  Brardi. 
  It 
  has 
  been 
  clearly 
  

   shown 
  by 
  Weiss 
  3 
  and 
  Zeiller 
  4 
  that 
  in 
  stems 
  of 
  the 
  S. 
  Brardi 
  type 
  there 
  

  

  1 
  ' 
  Bass, 
  houill. 
  Grard,' 
  pi. 
  x. 
  fig. 
  11. 
  

  

  2 
  Zeiller, 
  Bull. 
  Soc. 
  geol. 
  France, 
  ser. 
  3, 
  vol. 
  xxiii. 
  (1895) 
  pi. 
  viii. 
  

  

  3 
  Zeitsehr. 
  Deutsch. 
  geol. 
  G-esellsch. 
  vol. 
  xl. 
  (1888) 
  p. 
  565 
  ; 
  also 
  Weiss 
  & 
  

   Sterzel, 
  Abh. 
  k. 
  Preuss. 
  geol. 
  Landesanst. 
  1893, 
  p. 
  89. 
  

  

  4 
  Bull. 
  Soo. 
  geol. 
  France, 
  ser. 
  3, 
  vol. 
  xvni. 
  (1889) 
  p. 
  603. 
  

  

  