﻿164 
  PROCEEDINGS 
  OF 
  THE 
  GEOLOGICAL 
  SOCIETY. 
  [Feb. 
  3, 
  

  

  a 
  purple 
  tint, 
  and 
  the 
  latter 
  rests 
  conformably 
  upon 
  shale 
  which 
  

   equally 
  conforms 
  to 
  the 
  seam 
  of 
  coal 
  seen 
  at 
  Cullercoats 
  and 
  known 
  

   as 
  the 
  Hebburn 
  seam. 
  In 
  the 
  red 
  sandstones 
  immediately 
  above, 
  

   and 
  conformable 
  to 
  the 
  Hebburn 
  coal, 
  Plants 
  occur, 
  consisting 
  of 
  

   species 
  common 
  in 
  the 
  Coal-measures. 
  They 
  have 
  no 
  relation 
  to 
  

   the 
  true 
  Permian 
  Plants 
  such 
  as 
  are 
  obtained 
  from 
  the 
  marl-slate 
  

   of 
  Durham 
  and 
  its 
  equivalent 
  — 
  the 
  Hilton 
  leaf-beds 
  of 
  Westmore- 
  

   land 
  ; 
  and 
  the 
  evidence, 
  both 
  as 
  regards 
  stratigraphical 
  arrange- 
  

   ment 
  and 
  fossils, 
  removes 
  the 
  sandstones 
  north 
  of 
  Tynemouth 
  from 
  

   the 
  Lower 
  Permian 
  or 
  yellow 
  sandstones 
  of 
  the 
  Wear, 
  and 
  places 
  

   them 
  in 
  the 
  Carboniferous 
  formation. 
  

  

  With 
  regard 
  to 
  the 
  nature 
  of 
  the 
  Plants 
  of 
  the 
  true 
  Permian 
  strata, 
  

   they 
  have 
  a 
  widely 
  different 
  fades 
  from 
  that 
  which 
  the 
  carboniferous 
  

   Plants 
  present. 
  No 
  traces 
  of 
  either 
  Lepidodendron 
  or 
  Sigillarice 
  — 
  so 
  

   abundant 
  in 
  the 
  Coal-measures 
  — 
  have 
  been 
  hitherto 
  met 
  with 
  in 
  the 
  

   Permian 
  rocks 
  ; 
  and 
  with 
  reference 
  to 
  seeds, 
  while 
  Trigonocarpon, 
  a 
  

   fruit 
  appertaining 
  to 
  the 
  berry 
  -bearing 
  Coniferse, 
  occurs 
  in 
  the 
  Coal- 
  

   measures, 
  it 
  is 
  absent 
  from 
  the 
  Permian 
  group, 
  the 
  seeds 
  occurring 
  in 
  

   the 
  latter 
  being 
  the 
  products 
  of 
  cone-bearing 
  pines 
  which 
  make 
  their 
  

   appearance 
  for 
  the 
  first 
  time 
  in 
  the 
  Permian 
  formation. 
  

  

  Of 
  these 
  Coniferse 
  of 
  the 
  Permian 
  strata, 
  two 
  forms 
  of 
  Ullmania, 
  

   a 
  genus 
  unknown 
  in 
  the 
  Carboniferous 
  formation, 
  are 
  abundant, 
  the 
  

   cones 
  of 
  which 
  seem 
  to 
  have 
  been 
  of 
  small 
  size 
  ; 
  and 
  as 
  regards 
  

   Perns, 
  these 
  also 
  in 
  the 
  Permian 
  rocks 
  are 
  altogether 
  distinct 
  

   from 
  such 
  as 
  occur 
  in 
  the 
  Carboniferous 
  group. 
  The 
  fossil 
  plants 
  

   are, 
  therefore, 
  characteristic 
  of, 
  and 
  peculiar 
  to, 
  the 
  Permian 
  series 
  ; 
  

   they 
  also 
  indicate 
  different 
  climatal 
  conditions; 
  and, 
  if 
  we 
  may 
  

   judge 
  from 
  the 
  relative 
  size 
  of 
  the 
  cones 
  of 
  the 
  Gymnosperms, 
  we 
  

   should 
  infer 
  that 
  a 
  somewhat 
  lower 
  temperature 
  obtained 
  during 
  the 
  

   Permian 
  than 
  during 
  the 
  Carboniferous 
  epoch. 
  

  

  Although 
  there 
  is 
  no 
  great 
  band 
  of 
  Magnesian 
  Limestone 
  like 
  that 
  

   of 
  Durham 
  and 
  Yorkshire 
  to 
  mark 
  the 
  central 
  division 
  of 
  the 
  Per- 
  

   mian 
  rocks 
  of 
  the 
  north-west 
  of 
  England, 
  we 
  hold 
  that 
  the 
  series 
  we 
  

   have 
  described 
  in 
  the 
  Valley 
  of 
  the 
  Eden 
  is 
  much 
  fuller 
  and 
  thicker 
  

   than 
  its 
  equivalent 
  in 
  the 
  north-eastern 
  counties. 
  In 
  the 
  north-east'of 
  

   England, 
  not 
  only 
  is 
  the 
  Lower 
  Permian 
  orRothliegende 
  most 
  slenderly 
  

   and 
  imperfectly 
  represented, 
  but 
  the 
  highest 
  member 
  of 
  the 
  group 
  is 
  

   entirely 
  wanting. 
  On 
  the 
  other 
  hand, 
  the 
  splendid 
  development 
  of 
  

   the 
  Magnesian 
  Limestone, 
  in 
  its 
  range 
  from 
  the 
  coast 
  of 
  Durham 
  

   through 
  Yorkshire 
  and 
  into 
  Nottinghamshire, 
  is 
  so 
  much 
  superior 
  in 
  

   volume 
  to 
  its 
  feeble 
  equivalent 
  in 
  the 
  region 
  under 
  consideration, 
  

   that 
  some 
  geologists 
  may 
  be 
  induced 
  to 
  view 
  the 
  Upper 
  Sandstones 
  

   of 
  St. 
  Bees 
  and 
  Corby 
  as 
  synchronous 
  with 
  the 
  Upper 
  Magnesian 
  

   Limestones 
  and 
  red 
  marls 
  of 
  the 
  Yorkshire 
  series. 
  In 
  contrasting 
  the 
  

   siliceous 
  character 
  of 
  the 
  Permian 
  group 
  of 
  the 
  north-west 
  of 
  England 
  

   with 
  its 
  eminently 
  calcareous 
  development 
  in 
  Durham 
  and 
  Yorkshire, 
  

   it 
  is 
  to 
  be 
  borne 
  in 
  mind 
  that 
  even 
  the 
  latter 
  band, 
  when 
  it 
  trends 
  

   southwards 
  into 
  Nottinghamshire, 
  becomes 
  so 
  sandy 
  a 
  rock, 
  that 
  the 
  

   freestones 
  of 
  Mansfield, 
  of 
  both 
  red 
  and 
  whitish 
  colours, 
  might, 
  from 
  

   their 
  aspect, 
  be 
  mistaken 
  for 
  sandstones. 
  It 
  was 
  the 
  least 
  calcareous 
  

  

  