﻿144 
  PROCEEDINGS 
  OF 
  THE 
  GEOLOGICAL 
  SOCIETY. 
  [Feb. 
  3, 
  

  

  of 
  the 
  smaller 
  proportionate 
  mass 
  of 
  land 
  that 
  would 
  be 
  available 
  

   for 
  their 
  derivation, 
  and 
  the 
  greater 
  facility 
  with 
  which 
  they 
  would 
  

   be 
  denuded 
  on 
  mountain-tops. 
  It 
  is 
  only 
  surprising 
  that 
  any 
  record 
  

   whatever 
  has 
  been 
  left 
  of 
  the 
  presence 
  of 
  the 
  waters 
  over 
  the 
  steep 
  

   mountain-tops, 
  apparently 
  out 
  of 
  the 
  range 
  of 
  any 
  debris 
  excepting 
  

   that 
  derived 
  from 
  their 
  own 
  mass. 
  

  

  We 
  have, 
  however, 
  in 
  the 
  occurrence 
  of 
  drift 
  in 
  North 
  Wales 
  at 
  

   an 
  altitude 
  of 
  2300 
  feet, 
  evidence 
  of 
  a 
  submergence 
  vastly 
  greater 
  in 
  

   extent 
  than 
  that 
  necessary 
  to 
  produce 
  the 
  drift-phenomena 
  of 
  the 
  

   Severn 
  and 
  other 
  valleys. 
  WTiilst 
  we 
  can 
  have 
  no 
  certain 
  proof 
  

   of 
  the 
  limit 
  to 
  the 
  extent 
  or 
  duration 
  of 
  the 
  submergence, 
  we 
  may 
  

   be 
  allowed 
  to 
  conjecture 
  that 
  such 
  phenomena 
  as 
  those 
  developed 
  in 
  

   the 
  drift 
  of 
  the 
  Upper 
  Severn 
  Valley 
  may 
  have 
  been 
  but 
  compara- 
  

   tively 
  very 
  short 
  episodes 
  in 
  the 
  history 
  of 
  the 
  oscillation 
  of 
  level 
  in 
  

   which 
  their 
  deposition 
  and 
  subsequent 
  denudation 
  was 
  included 
  ; 
  the 
  

   first 
  during 
  the 
  commencement 
  of 
  the 
  submergence, 
  and 
  the 
  second 
  

   when 
  the 
  present 
  level 
  had 
  been 
  nearly 
  recovered, 
  and 
  the 
  long-sub- 
  

   merged 
  land 
  and 
  its 
  drift-beds 
  were 
  again 
  appearing 
  above 
  the 
  

   waters, 
  presenting 
  their 
  surface 
  along 
  successive 
  new 
  coast-lines 
  to 
  

   the 
  eroding 
  action 
  of 
  the 
  waves, 
  and 
  soon 
  to 
  be 
  repeopled 
  with 
  ter- 
  

   restrial 
  life. 
  

  

  February 
  3, 
  1864. 
  

  

  Charles 
  William 
  Yilliers- 
  Bradford, 
  Esq., 
  B.A., 
  of 
  St. 
  Catherine's 
  

   College, 
  Cambridge, 
  and 
  Greatham 
  Rectory, 
  Petersfield, 
  was 
  elected 
  

   a 
  Fellow. 
  

  

  The 
  following 
  communication 
  was 
  read 
  : 
  — 
  

  

  On 
  the 
  Permian 
  Rocks 
  of 
  the 
  North-West 
  of 
  England, 
  and 
  their 
  

   Extension 
  into 
  Scotland. 
  By 
  Sir 
  Roderick 
  I. 
  Murchison, 
  K.C.B., 
  

   D.C.L., 
  F.R.S., 
  F.G.S., 
  &c, 
  Director-General 
  of 
  the 
  Geological 
  

   Survey 
  of 
  Great 
  Britain 
  ; 
  and 
  Robert 
  Harkness, 
  F.R.S., 
  F.G.S., 
  

   Professor 
  of 
  Geology, 
  Queen's 
  College, 
  Cork. 
  

  

  Introduction. 
  By 
  Sir 
  R. 
  I. 
  Murchison. 
  

  

  The 
  data 
  which 
  are 
  presented 
  to 
  the 
  Society 
  in 
  the 
  following 
  Memoir 
  

   have 
  for 
  the 
  most 
  part 
  been 
  established 
  by 
  the 
  researches 
  of 
  my 
  as- 
  

   sociate, 
  Professor 
  Harkness, 
  whose 
  previous 
  labours* 
  on 
  the 
  same 
  

   subject 
  are 
  well 
  known 
  to 
  geologists, 
  and 
  who, 
  with 
  one 
  exception, 
  

   has 
  prepared 
  all 
  the 
  maps 
  and 
  coloured 
  sections 
  which 
  are 
  now 
  ex- 
  

   hibited. 
  

  

  In 
  the 
  following 
  Memoir, 
  as 
  well 
  as 
  in 
  a 
  brief 
  outline 
  of 
  the 
  same 
  

   subject 
  communicated 
  by 
  us 
  to 
  the 
  last 
  Meeting 
  of 
  the 
  British 
  Asso- 
  

   ciation 
  at 
  Newcastle, 
  we 
  propound 
  that 
  which 
  is, 
  in 
  truth, 
  a 
  new 
  

   view 
  of 
  the 
  aggregate 
  of 
  the 
  component 
  parts 
  of 
  the 
  Permian 
  Group 
  

   in 
  Britain. 
  By 
  this 
  arrangement 
  we 
  place 
  these 
  rocks 
  in 
  direct 
  

  

  * 
  Quart. 
  Journ. 
  Geol. 
  Soc. 
  vol. 
  xviii. 
  p. 
  20G. 
  

  

  