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

  

  associated 
  with 
  them 
  have 
  been 
  in 
  most 
  cases 
  so 
  profoundly 
  altered, 
  

   and 
  furnish 
  also 
  evidence 
  of 
  having 
  been 
  deposited 
  in 
  areas 
  so 
  greatly 
  

   disturbed, 
  that 
  it 
  would 
  hardly 
  be 
  possible 
  to 
  conceive 
  circumstances 
  

   less 
  favourable 
  to 
  the 
  presence 
  or 
  the 
  retention 
  of 
  any 
  remnants 
  of 
  

   the 
  life 
  of 
  the 
  period. 
  When 
  we 
  all 
  believed 
  that 
  the 
  20,000 
  or 
  

   30,000 
  feet 
  tabled 
  as 
  the 
  estimate 
  of 
  the 
  thickness 
  of 
  the 
  Lauren- 
  

   tian 
  rocks 
  was 
  a 
  sign 
  of 
  the 
  accumulation 
  in 
  marine 
  areas 
  of 
  

   sediments 
  of 
  that 
  thickness, 
  it 
  certainly 
  seemed 
  strange 
  to 
  any 
  one 
  

   who 
  believed 
  in 
  evolution 
  that 
  no 
  clear 
  and 
  undisputed 
  evidence 
  of 
  

   the 
  life 
  of 
  the 
  era 
  had 
  been 
  discovered 
  anywhere. 
  It 
  seemed 
  

   difficult 
  to 
  conceive 
  that 
  the 
  great 
  marine 
  areas 
  of 
  the 
  time 
  could 
  

   be 
  devoid 
  of 
  life 
  ; 
  for 
  the 
  teachings 
  of 
  Nature 
  are 
  clear 
  enough 
  in 
  

   showing 
  that, 
  where 
  the 
  circumstances 
  are 
  in 
  any 
  way 
  suitable, 
  life 
  

   in 
  some 
  form 
  is 
  sure 
  to 
  exist. 
  There 
  seems 
  to 
  be 
  plenty 
  of 
  evidence 
  

   to 
  show 
  that 
  the 
  sea, 
  in 
  late 
  pre-Cambrian 
  times 
  at 
  least, 
  could 
  not 
  

   have 
  varied 
  materially 
  in 
  its 
  temperature 
  from 
  that 
  prevailing 
  in 
  

   Cambrian 
  time 
  ; 
  therefore 
  we 
  are 
  led 
  to 
  believe 
  that 
  there 
  must 
  have 
  

   been 
  an 
  abundance 
  of 
  life 
  in 
  the 
  sea 
  where 
  there 
  were 
  no 
  markedly 
  

   disturbing 
  influences 
  at 
  work. 
  Why, 
  then, 
  is 
  it 
  that 
  after 
  so 
  many 
  

   years 
  of 
  diligent 
  search 
  we 
  have 
  still 
  so 
  poor 
  a 
  record 
  of 
  the 
  life 
  

   of 
  the 
  era 
  ? 
  I 
  think 
  that 
  a 
  careful 
  examination 
  of 
  the 
  materials 
  of 
  

   which 
  the 
  pre-Cambrian 
  rocks 
  are 
  composed, 
  and 
  of 
  the 
  contents 
  

   of 
  the 
  Cambrian 
  conglomerates, 
  tends 
  to 
  show 
  that, 
  up 
  to 
  the 
  

   present, 
  we 
  have 
  not 
  succeeded 
  in 
  meeting 
  in 
  any 
  area 
  with 
  

   sediments 
  which 
  give 
  sure 
  indications 
  of 
  having 
  been 
  deposited 
  

   under 
  conditions 
  favourable 
  to 
  animal 
  life. 
  In 
  the 
  grits 
  and 
  

   sandstones, 
  both 
  in 
  situ 
  and 
  when 
  found 
  as 
  fragments 
  in 
  the 
  con- 
  

   glomerates, 
  there 
  are 
  indications 
  of 
  worm-tubes 
  and 
  tracks, 
  as 
  

   in 
  later 
  rocks. 
  But 
  finer 
  deposits 
  and 
  calcareous 
  beds 
  are 
  so 
  rare 
  

   that 
  we 
  are 
  compelled 
  to 
  believe 
  that 
  we 
  are 
  almost 
  everywhere 
  

   dealing 
  with 
  shore- 
  and 
  shallow-water 
  deposits 
  accumulating 
  in 
  

   highly-disturbed 
  areas 
  subject 
  to 
  frequent 
  volcanic 
  outbursts. 
  

  

  This 
  question 
  has 
  greatly 
  interested 
  me 
  since 
  the 
  time 
  when 
  we 
  

   discovered 
  that 
  the 
  pre-Cambrian 
  rocks 
  at 
  St. 
  David's 
  were 
  mainly 
  

   of 
  volcanic 
  origin. 
  When 
  we 
  first 
  assumed 
  that 
  there 
  was 
  an 
  

   important 
  series 
  of 
  rocks 
  at 
  St. 
  David's 
  older 
  than 
  the 
  basal 
  

   Cambrian 
  conglomerates, 
  we 
  believed 
  that 
  they 
  were 
  mainly 
  

   ordinary 
  sediments 
  that 
  had 
  been 
  greatly 
  metamorphosed, 
  fol- 
  

   lowing 
  in 
  this 
  view 
  the 
  usual 
  opinion 
  held 
  by 
  petrologists 
  and 
  

   geologists 
  at 
  that 
  time. 
  In 
  the 
  year 
  1877, 
  however, 
  I 
  commu- 
  

   nicated 
  a 
  paper 
  to 
  this 
  Society 
  in 
  which 
  evidence 
  was 
  given 
  to 
  show 
  

  

  