﻿"^°1« 
  53-] 
  ANNIVERSARY 
  ADDRESS 
  OF 
  THE 
  PRESIDENT. 
  lxvil 
  

  

  purple 
  slates, 
  and 
  this 
  was 
  afterwards 
  adopted 
  as 
  the 
  line 
  between 
  

   the 
  Silurian 
  and 
  Cambrian 
  strata.' 
  

  

  The 
  Longmynd 
  Rocks 
  up 
  to 
  a 
  comparatively 
  recent 
  period 
  were 
  

   always 
  included 
  in 
  the 
  Cambrian, 
  but 
  of 
  late 
  years 
  the 
  tendency 
  has 
  

   been 
  to 
  associate 
  them 
  with 
  the 
  pre-Cambrian. 
  If 
  they 
  can 
  be 
  

   proved 
  to 
  be 
  without 
  doubt 
  of 
  pre-Cambrian 
  age, 
  unusual 
  interest 
  

   will 
  be 
  attached 
  to 
  them 
  owing 
  to 
  the 
  fact 
  that 
  many 
  years 
  ago 
  

   Mr. 
  Salter 
  found 
  in 
  them 
  burrows 
  of 
  annelids 
  which 
  he 
  described 
  

   under 
  the 
  name 
  of 
  Arenicolites 
  didyma, 
  and 
  also 
  what 
  he 
  considered 
  

   to 
  be 
  a 
  part 
  of 
  a 
  trilobite 
  under 
  the 
  name 
  of 
  Palceopyge 
  Ramsayi. 
  

  

  The 
  Cambrian 
  Period. 
  

  

  It 
  had 
  been 
  shown 
  by 
  Salter 
  and 
  myself 
  before 
  the 
  year 
  1867 
  that 
  

   a 
  very 
  rich 
  fauna 
  occurred 
  in 
  the 
  Menevian 
  beds, 
  which 
  rested 
  directly 
  

   on 
  the 
  red, 
  purple, 
  and 
  green 
  grits 
  and 
  slates, 
  in 
  North 
  and 
  South 
  

   Wales 
  ; 
  but 
  up 
  to 
  that 
  year 
  no 
  organisms 
  had 
  been 
  found 
  in 
  the 
  

   latter, 
  the 
  only 
  rocks 
  recognized 
  as 
  Cambrian 
  by 
  Sir 
  E. 
  Murchison 
  

   and 
  the 
  Geological 
  Survey. 
  Curiously, 
  however, 
  in 
  that 
  year 
  I 
  found 
  

   in 
  the 
  red 
  rocks 
  underlying 
  the 
  Menevian 
  beds 
  at 
  St. 
  David's 
  a 
  small 
  

   Lingida, 
  and 
  this 
  was 
  described 
  in 
  a 
  paper 
  by 
  Mr. 
  Salter 
  and 
  

   myself 
  at 
  a 
  meeting 
  of 
  the 
  Geological 
  Society 
  on 
  June 
  19th, 
  1867, 
  

   and 
  fortunately 
  in 
  time 
  for 
  Sir 
  K. 
  Murchison 
  to 
  add 
  the 
  following 
  

   note 
  in 
  the 
  Appendix 
  (p. 
  550) 
  to 
  the 
  edition 
  of 
  ' 
  Siluria 
  ' 
  which 
  

   contained 
  the 
  statement 
  already 
  referred 
  to 
  : 
  — 
  ' 
  At 
  the 
  meeting 
  

   of 
  the 
  Geological 
  Society 
  on 
  June 
  19th, 
  1867, 
  Mr. 
  J. 
  W. 
  Salter 
  

   read 
  an 
  account 
  of 
  the 
  discovery 
  of 
  a 
  minute 
  Lingulella 
  in 
  the 
  red 
  

   Cambrian 
  rocks 
  of 
  St. 
  David's, 
  which 
  there 
  underlie 
  the 
  Primordial 
  

   Silurian 
  (mihi). 
  According 
  to 
  my 
  view 
  (and 
  I 
  am 
  entitled 
  to 
  judge 
  

   by 
  acquaintance 
  with 
  both 
  districts), 
  the 
  rocks 
  in 
  which 
  this 
  small 
  

   fossil 
  was 
  found 
  may 
  be 
  paralleled 
  in 
  age 
  with 
  the 
  uppermost 
  or 
  red 
  

   portion 
  of 
  my 
  original 
  Cambrian 
  of 
  the 
  Longmynd 
  (1835).' 
  

  

  This 
  was 
  the 
  first 
  admission 
  on 
  the 
  part 
  of 
  the 
  Geological 
  Survey 
  

   that 
  ' 
  Cambrian 
  ' 
  rocks, 
  or 
  those 
  classed 
  by 
  them 
  under 
  that 
  name 
  

   in 
  Wales, 
  contained 
  any 
  evidence 
  of 
  the 
  life 
  of 
  that 
  period. 
  In 
  

   subsequent 
  years 
  I 
  was 
  able 
  to 
  show 
  that 
  the 
  whole 
  of 
  the 
  rocks 
  

   coloured 
  as 
  unaltered 
  Cambrian 
  at 
  St. 
  David's 
  to 
  their 
  very 
  base 
  

   contained 
  fossils, 
  and 
  that 
  the 
  seas 
  in 
  which 
  the 
  deposits 
  had 
  accu- 
  

   mulated 
  must 
  have 
  teemed 
  with 
  life. 
  Since 
  then, 
  through 
  the 
  

   researches 
  of 
  Dr. 
  Callaway 
  and 
  Prof. 
  Lapworth 
  in 
  Shropshire, 
  and 
  of 
  

   the 
  officers 
  of 
  the 
  Geological 
  Survey 
  in 
  the 
  North-west 
  of 
  Scotland,- 
  

  

  