﻿PEN-Y-GLOG 
  SLATE-QUARRY, 
  NORTH 
  WALES. 
  101 
  

  

  EXPLANATION 
  OF 
  PLATE 
  III. 
  

  

  Fig. 
  1. 
  Berwynia 
  Carruthersi 
  : 
  decorticated 
  branch. 
  Natural 
  size. 
  

  

  2. 
  : 
  branch 
  showing 
  cortical 
  layer, 
  and 
  probably 
  at 
  a 
  the 
  posi- 
  

   tions 
  of 
  some 
  leaves. 
  Nat. 
  size. 
  

  

  3. 
  ■ 
  (?) 
  : 
  portion 
  of 
  root, 
  showing 
  scars 
  and 
  fragments 
  of 
  rootlets. 
  

  

  Nat. 
  size. 
  Sa 
  & 
  3b, 
  scars 
  and 
  rootlets 
  : 
  X 
  2. 
  

  

  4. 
  (?) 
  : 
  fragment 
  of 
  a 
  capsule 
  containing 
  numerous 
  spore-like 
  

  

  bodies. 
  Nat. 
  size. 
  4 
  a, 
  spore-like 
  bodies 
  : 
  X 
  8. 
  

  

  Discussion. 
  

  

  Mr. 
  Carruthers 
  complimented 
  Dr. 
  Hicks 
  upon 
  his 
  persevering 
  

   investigations 
  of 
  these 
  unpromising 
  rocks. 
  Not 
  much 
  could 
  be 
  

   said 
  about 
  the 
  materials. 
  The 
  carbon 
  (in 
  the 
  condition 
  of 
  anthra- 
  

   cite) 
  of 
  the 
  plants 
  was 
  remarkably 
  preserved, 
  because 
  the 
  remains 
  

   had 
  been 
  sealed 
  up 
  in 
  clay 
  ; 
  but 
  it 
  was 
  in 
  such 
  a 
  condition 
  that 
  not 
  

   much 
  could 
  he 
  determined 
  as 
  to 
  the 
  plants. 
  The 
  outward 
  form, 
  how- 
  

   ever, 
  was 
  to 
  some 
  extent 
  preserved 
  ; 
  and 
  from 
  indications, 
  though 
  

   obscure, 
  he 
  considered 
  the 
  remains 
  not 
  Algae, 
  like 
  those 
  formerly 
  

   discovered 
  "by 
  Dr. 
  Hicks, 
  but 
  higher 
  forms 
  of 
  dry-land 
  vegetation 
  

   belonging 
  to 
  the 
  Lycopodiacese. 
  

  

  Dr. 
  Sterry 
  Hunt 
  said 
  he 
  agreed 
  with 
  Mr. 
  Carruthers 
  as 
  to 
  the 
  

   cause 
  of 
  these 
  remains 
  being 
  anthracitic. 
  He 
  thought, 
  as 
  a 
  rule, 
  

   that 
  conversion 
  into 
  anthracite 
  was 
  due 
  not 
  to 
  heat 
  but 
  to 
  circum- 
  

   stances 
  of 
  deposition. 
  Where 
  there 
  was 
  free 
  passage 
  for 
  atmospheric 
  

   water, 
  anthracite 
  was 
  likely 
  to 
  result. 
  

  

  Prof. 
  Rupert 
  Jones 
  said 
  that 
  Principal 
  Dawson 
  had 
  called 
  atten- 
  

   tion 
  to 
  the 
  parts 
  of 
  the 
  old 
  jungles 
  which 
  had 
  helped 
  to 
  make 
  coal. 
  

   Those 
  portions 
  of 
  the 
  fallen 
  wood 
  which 
  had 
  remained 
  for 
  a 
  time 
  

   exposed 
  to 
  the 
  air 
  had 
  been 
  converted 
  into 
  mineral 
  charcoal. 
  

  

  Prof. 
  Duncan 
  doubted 
  whether 
  all 
  the 
  remains 
  were 
  of 
  vegetable 
  

   origin, 
  and 
  said 
  that 
  dichotomy 
  did 
  not 
  prove 
  the 
  remains 
  to 
  be 
  plants. 
  

   He 
  thought 
  some 
  of 
  the 
  markings 
  might 
  be 
  merely 
  mineral. 
  Others, 
  

   however, 
  he 
  thought 
  were 
  true 
  plant-remains. 
  

  

  Mr. 
  Carruthers, 
  after 
  pointing 
  out 
  that 
  the 
  metamorphic 
  action 
  

   which 
  had 
  converted 
  the 
  substance 
  of 
  the 
  plant 
  into 
  anthracite 
  

   would 
  leave 
  no 
  tissue 
  that 
  could 
  be 
  distinguished, 
  stated 
  that 
  his 
  

   experience 
  as 
  to 
  the 
  remains 
  of 
  plants 
  in 
  the 
  state 
  of 
  carbon 
  occur- 
  

   ring 
  in 
  arenaceous 
  rocks 
  differed 
  from 
  Dr. 
  Sterry 
  Hunt's 
  ; 
  for 
  he 
  had 
  

   never 
  found 
  that 
  the 
  carbon 
  remained 
  in 
  these 
  porous 
  rocks. 
  It 
  was 
  

   not 
  so 
  in 
  the 
  Carboniferous 
  Sandstones 
  of 
  Scotland. 
  

  

  Dr. 
  Woodward 
  said 
  plant-remains 
  (Glyptodendron) 
  had 
  been 
  found 
  

   in 
  America 
  slightly 
  lower 
  than 
  those 
  of 
  Dr. 
  Hicks 
  ; 
  so 
  there 
  was 
  no 
  

   improbability 
  in 
  the 
  latter 
  being 
  plant-remains. 
  

  

  Mr. 
  Tawney 
  asked 
  if 
  there 
  were 
  not 
  marks 
  of 
  Graptolites 
  on 
  the 
  

   slabs, 
  and 
  how 
  would 
  these 
  be 
  associated 
  with 
  land-plants 
  ? 
  

  

  Prof. 
  Morris 
  thought 
  some 
  of 
  the 
  markings 
  might 
  not 
  be 
  con- 
  

  

  