﻿Vol. 
  53.] 
  ANNIVERSARY 
  ADDRESS 
  OF 
  THE 
  PRESIDENT. 
  lxxxix 
  

  

  Assoc, 
  vol. 
  vii. 
  1881, 
  p. 
  73), 
  I 
  spoke 
  with 
  some 
  doubt 
  as 
  to 
  the 
  

   evidence 
  then 
  available 
  to 
  show 
  the 
  occurrence 
  of 
  pre-Cainbrian 
  

   rocks 
  in 
  Cornwall, 
  but 
  said 
  : 
  — 
  ' 
  At 
  present, 
  however, 
  it 
  would 
  be 
  

   unsafe 
  to 
  theorize 
  upon 
  the 
  evidence 
  available, 
  but 
  no 
  harm 
  can 
  

   arise 
  from 
  referring 
  briefly 
  to 
  the 
  facts. 
  It 
  is 
  well 
  known 
  that 
  the 
  

   Eddystone 
  lighthouse 
  is 
  built 
  upon 
  rocks 
  of 
  a 
  gneissose 
  type, 
  some 
  

   massive, 
  others 
  more 
  schistose. 
  These 
  gneisses 
  appear 
  to 
  be 
  of 
  the 
  

   true 
  type 
  of 
  the 
  older 
  or 
  granitoid 
  kind, 
  hence 
  rendering 
  it 
  probable 
  

   that 
  in 
  the 
  Channel, 
  at 
  least, 
  a 
  ridge 
  of 
  these 
  older 
  rocks 
  occurs.' 
  

  

  Prof. 
  Bonney, 
  from 
  the 
  result 
  of 
  careful 
  researches 
  in 
  the 
  Lizard 
  

   district, 
  has 
  arrived 
  at 
  the 
  conclusion 
  that 
  at 
  any 
  rate 
  the 
  gneisses, 
  

   hornblende-, 
  and 
  other 
  schists 
  may 
  probably 
  be 
  of 
  pre-Cambrian 
  

   age, 
  and 
  the 
  researches 
  of 
  Mr. 
  J. 
  H. 
  Collins, 
  Mr. 
  Howard 
  Fox, 
  and 
  

   Mr. 
  J. 
  J. 
  H. 
  Teall 
  have 
  also 
  shown 
  that 
  rocks 
  of 
  Ordovician 
  age 
  are 
  

   faulted 
  against 
  the 
  gneissose 
  rocks 
  at 
  several 
  points 
  in 
  that 
  district. 
  

   The 
  finding 
  of 
  radiolarian 
  cherts 
  in 
  these 
  Ordovician 
  rocks 
  by 
  

   Messrs* 
  Pox 
  & 
  Teall 
  is 
  of 
  interest 
  as 
  indicating 
  that 
  at 
  least 
  

   moderately 
  deep-water 
  deposits 
  were 
  being 
  thrown 
  down 
  in 
  this 
  

   area 
  early 
  in 
  Palaeozoic 
  time. 
  In 
  Quart. 
  Journ. 
  Geol. 
  Soc. 
  vol. 
  xxxi. 
  

   1875, 
  I 
  published 
  a 
  map 
  of 
  the 
  European 
  area, 
  showing 
  the 
  com- 
  

   parative 
  thickness 
  and 
  depth 
  of 
  deposition 
  of 
  the 
  Cambrian 
  and 
  

   Lower 
  Silurian 
  rocks 
  in 
  different 
  areas, 
  and 
  one 
  of 
  the 
  lines 
  of 
  

   greatest 
  depression 
  was 
  shown 
  to 
  run 
  in 
  a 
  direction 
  from 
  S.W. 
  to 
  

   N.E. 
  south 
  of 
  the 
  English 
  Channel. 
  In 
  that 
  paper 
  also 
  I 
  said 
  that 
  

   the 
  evidence 
  seemed 
  to 
  show 
  that 
  moderately 
  deep 
  water 
  covered 
  

   many 
  of 
  the 
  western 
  areas 
  in 
  Europe 
  at 
  that 
  time. 
  Prof. 
  Bonney 
  

   has 
  suggested 
  that 
  the 
  micaceous 
  and 
  chloritic 
  schists 
  at 
  Start 
  Point 
  

   which 
  are 
  faulted 
  against 
  slaty 
  rocks, 
  probably 
  of 
  Devonian 
  age, 
  

   are 
  pre-Cambrian. 
  These 
  schists, 
  he 
  says, 
  are 
  almost 
  identical 
  

   with 
  some 
  of 
  the 
  members 
  of 
  the 
  great 
  upper 
  group 
  of 
  schists 
  in 
  

   the 
  Alps. 
  Those 
  who 
  know 
  the 
  amount 
  of 
  faulting 
  and 
  crushing 
  

   which 
  has 
  taken 
  place 
  in 
  the 
  rocks 
  of 
  South 
  Devon 
  can 
  readily 
  

   realize 
  why, 
  if 
  these 
  be 
  pre-Cambrian 
  rocks, 
  there 
  is 
  no 
  actual 
  

   evidence 
  showing 
  Lower 
  Palaeozoic 
  rocks 
  in 
  contact 
  with 
  them. 
  

  

  The 
  researches 
  of 
  the 
  Eev. 
  E. 
  Hill, 
  Prof. 
  Bonney, 
  Dr. 
  Barrois, 
  

   M. 
  Bigot, 
  and 
  Prof, 
  de 
  Lapparent 
  in 
  the 
  Channel 
  Islands 
  and 
  

   neighbouring 
  areas 
  in 
  Normandy 
  and 
  Britanny 
  show 
  clearly 
  that 
  

   there 
  both 
  Upper 
  and 
  Lower 
  Cambrian 
  rocks 
  repose 
  unconformably 
  

   upon 
  pre-Cambrian 
  gneiss-rocks 
  and 
  felstones, 
  the 
  latter 
  resembling 
  

   closely 
  those 
  which 
  occur 
  in 
  the 
  volcanic 
  series 
  of 
  Wales 
  and 
  

   Shropshire. 
  I 
  am 
  told 
  by 
  Prof. 
  Bonney 
  that 
  in 
  Jersey 
  felstones 
  

   and 
  coarser 
  crystalline 
  igneous 
  rocks 
  underlie 
  a 
  conglomerate 
  

   accepted 
  now 
  as 
  basal 
  Cambrian, 
  and 
  some 
  of 
  the 
  crystallines 
  are 
  

  

  