﻿So 
  PROCEEDINGS 
  OF 
  THE 
  GEOLOGICAL 
  SOCIETY. 
  

  

  The 
  following 
  communications 
  were 
  read 
  : 
  — 
  

  

  1. 
  " 
  Supplementary 
  Xote 
  to 
  a 
  paper 
  on 
  the 
  Rocks 
  of 
  the 
  Atlantic 
  

   Coast 
  of 
  Canada." 
  By 
  Sir 
  J. 
  W. 
  Dawson, 
  K.C.M.G., 
  F.E.S., 
  F.G.S. 
  

  

  In 
  my 
  paper 
  in 
  the 
  ' 
  Geological 
  Journal 
  ' 
  for 
  November, 
  1888, 
  I 
  

   have 
  referred 
  (p. 
  805) 
  to 
  the 
  Olenellus-faxma 
  as 
  characterizing 
  the 
  

   Middle 
  Cambrian. 
  This 
  fauna 
  should, 
  I 
  have 
  now 
  no 
  doubt, 
  from 
  

   the 
  recently 
  published 
  observations 
  of 
  Walcott 
  and 
  Matthew, 
  be 
  

   regarded 
  as 
  characteristic 
  of 
  the 
  Upper 
  Member 
  of 
  the 
  Lower 
  Cam- 
  

   brian, 
  that 
  is, 
  below 
  the 
  horizon 
  of 
  Paradoxides. 
  From 
  this 
  arises 
  

   a 
  new 
  view 
  of 
  the 
  ph}"sical 
  geography 
  of 
  the 
  period, 
  namely, 
  that 
  

   the 
  Lower 
  Cambrian 
  was, 
  in 
  America, 
  a 
  period 
  of 
  continental 
  

   depression, 
  and 
  the 
  Middle 
  Cambrian 
  a 
  period 
  of 
  continental 
  eleva- 
  

   tion. 
  This 
  leads 
  to 
  the 
  important 
  conclusion 
  that 
  a 
  time 
  of 
  elevation 
  

   intervened 
  between 
  the 
  Huronian 
  and 
  the 
  early 
  Cambrian, 
  and 
  which 
  

   may 
  represent 
  the 
  apparent 
  gap 
  between 
  these 
  systems 
  in 
  Eastern 
  

   America. 
  This 
  new 
  view 
  is 
  so 
  important 
  that 
  I 
  think 
  it 
  deserves 
  a 
  

   special 
  mention 
  in 
  connexion 
  with 
  the 
  probability 
  that 
  the 
  Huronian 
  

   and 
  Kewenian 
  beds 
  are 
  of 
  littoral 
  origin. 
  

  

  Discrssiox. 
  

  

  Dr. 
  Hlnde 
  observed 
  that 
  a 
  paper 
  published 
  by 
  Prof. 
  Brogger 
  in 
  

   1886*, 
  on 
  the 
  age 
  of 
  the 
  Olenellus-zoJie 
  in 
  North 
  America, 
  had 
  appa- 
  

   rently 
  escaped 
  the 
  notice 
  of 
  Sir 
  J. 
  W. 
  Dawson. 
  In 
  it 
  this 
  author 
  

   pointed 
  out 
  that 
  in 
  Scandinavia, 
  where 
  the 
  succession 
  was 
  unmis- 
  

   takably 
  clear, 
  the 
  Olenellns-zcme 
  was 
  at 
  the 
  base 
  of 
  the 
  Cambrian, 
  

   and 
  was 
  succeeded 
  above 
  by 
  the 
  Paradoxides-zone, 
  and 
  that 
  the 
  

   same 
  order 
  of 
  succession 
  would 
  in 
  all 
  probability 
  be 
  likewise 
  found 
  

   in 
  North 
  America. 
  This 
  prediction 
  had 
  been 
  verified 
  by 
  Mr. 
  Walcott 
  

   this 
  last 
  summer, 
  and 
  the 
  views 
  hitherto 
  maintained 
  by 
  the 
  Ame- 
  

   rican 
  geologists 
  as 
  to 
  the 
  earlier 
  age 
  of 
  the 
  Paradoxides-\>e&s> 
  are 
  

   now 
  given 
  up. 
  

  

  Dr. 
  Hicks 
  confirmed 
  the 
  above 
  remarks. 
  Hitherto, 
  in 
  the 
  St. 
  

   David's 
  district, 
  no 
  definite 
  Olenellus-faunsi 
  had 
  been 
  discovered, 
  but 
  

   he 
  believed 
  that 
  the 
  horizon 
  was 
  indicated 
  by 
  the 
  Lingidella-primceva 
  

   zone, 
  which 
  occurs 
  near 
  the 
  base 
  of 
  the 
  Cambrian 
  and 
  several 
  

   hundred 
  feet 
  below 
  the 
  lowest 
  Paradoxides 
  -beds. 
  In 
  Shropshire, 
  

   on 
  the 
  other 
  hand, 
  the 
  Olenellus-famia, 
  had 
  been 
  found, 
  but 
  not 
  

   that 
  associated 
  with 
  Paradoxides. 
  

  

  Mr. 
  Mark 
  felt 
  sure 
  that 
  the 
  Olenellus-question 
  would 
  attain 
  to 
  

   importance 
  before 
  long. 
  Prof. 
  Brogger 
  had 
  determined 
  the 
  true 
  

   position 
  of 
  the 
  beds 
  with 
  certainty. 
  He 
  believed 
  that 
  the 
  Georgia 
  

   group 
  contained 
  beds 
  of 
  newer 
  age 
  interfolded 
  with 
  the 
  Olenellus- 
  

   beds. 
  

  

  2. 
  " 
  The 
  Occurrence 
  of 
  Colloid 
  Silica 
  in 
  the 
  Lower 
  Chalk 
  of 
  

   Berkshire 
  and 
  Wiltshire." 
  By 
  W. 
  Hill, 
  Esq., 
  F.G.S., 
  and 
  A. 
  J. 
  

   Jukes-Browne, 
  Esq., 
  F.G.S. 
  

  

  3. 
  " 
  Xote 
  on 
  the 
  pelvis 
  of 
  Omithqpsis." 
  By 
  Prof. 
  H. 
  G. 
  Seelev, 
  

   F.K.S., 
  F.G.S. 
  

  

  * 
  Geul. 
  For. 
  i 
  Stockh. 
  Fdrhandl. 
  Bel. 
  viii. 
  p. 
  18:2. 
  

  

  