﻿390 
  ON" 
  THE 
  ROCKS 
  OP 
  ALDER5TEY 
  AND 
  THE 
  CASQTJETS. 
  

  

  the 
  unevenness 
  of 
  the 
  floor 
  in 
  this 
  part 
  of 
  Europe 
  is 
  consequently 
  

   similar 
  to 
  that 
  of 
  Northern 
  Scotland. 
  

  

  Dr. 
  Woodward 
  referred 
  to 
  a 
  supposed 
  Oldhamia, 
  and 
  pointed 
  

   out 
  that 
  the 
  markings 
  were 
  due 
  to 
  the 
  action 
  of 
  recent 
  Limpets. 
  

  

  Dr. 
  Hicks 
  referred 
  to 
  the 
  researches 
  of 
  M. 
  Bigot, 
  and 
  commented 
  

   upon 
  his 
  excellent 
  work. 
  The 
  views 
  put 
  forward 
  hy 
  Mr. 
  Hill, 
  like 
  

   those 
  of 
  M. 
  Bigot, 
  seemed 
  to 
  confirm 
  the 
  Pre-Cambrian 
  age 
  of 
  the 
  

   rocks 
  in 
  Normandy 
  and 
  Brittany, 
  originally 
  determined 
  as 
  such 
  by 
  

   M. 
  Hebert, 
  

  

  Mr. 
  Rutley 
  asked 
  for 
  further 
  information 
  as 
  to 
  the 
  felsites 
  of 
  

   Boulay 
  Bay, 
  arid 
  especially 
  with 
  regard 
  to 
  their 
  age. 
  

  

  Mr. 
  Teall 
  said 
  that 
  he 
  had 
  understood 
  that 
  the 
  Boulay-Bay 
  fel- 
  

   sites 
  must 
  be 
  Pre-Upper 
  Cambrian, 
  which 
  brought 
  them 
  into 
  ap- 
  

   parent 
  relationship 
  with 
  the 
  very 
  similar 
  Wrekin 
  rocks. 
  

  

  Mr. 
  Cole 
  commented 
  on 
  the 
  wide 
  bearing 
  of 
  the 
  question 
  of 
  

   the 
  age 
  of 
  these 
  rhyolites. 
  French 
  geologists 
  had 
  maintained 
  that 
  

   the 
  pyromerides 
  containing 
  quartz 
  were 
  of 
  Silurian 
  age 
  ; 
  those 
  of 
  

   Permian 
  age 
  contained 
  chalcedony, 
  and 
  those 
  of 
  more 
  modern 
  

   origin 
  opal. 
  The 
  removal 
  of 
  the 
  Boulay-Bay 
  rocks 
  from 
  those 
  of 
  

   the 
  Vosges 
  was 
  opposed 
  to 
  this 
  mineralogical 
  view. 
  

  

  The 
  Author 
  observed 
  that 
  the 
  ancient 
  floor 
  of 
  crushed 
  rocks 
  had 
  

   not 
  escaped 
  his 
  attention. 
  Mr. 
  Etheridge 
  had 
  observed 
  that 
  the 
  

   simulations 
  of 
  fossils 
  resembled 
  markings 
  of 
  modern 
  Mollusca. 
  A 
  

   great 
  thickness 
  of 
  rhyolites 
  occurred 
  in 
  Jersey, 
  which 
  was 
  con- 
  

   sidered 
  to 
  be 
  one 
  series. 
  Only 
  certain 
  varieties 
  of 
  these 
  could 
  be 
  

   identified 
  as 
  pebbles 
  in 
  the 
  sedimentary 
  rocks. 
  Among 
  these 
  

   pebbles 
  he 
  had 
  not 
  actually 
  recognized 
  pyromerides 
  ; 
  but 
  he 
  quite 
  

   agreed 
  with 
  the 
  view 
  that 
  the 
  age 
  of 
  the 
  Boulay-Bay 
  rocks 
  was 
  the 
  

   age 
  of 
  the 
  other 
  rhyolites. 
  

  

  