﻿220 
  PROCEEDINGS 
  OF 
  THE 
  GEOLOGICAL 
  SOCIETY. 
  [Mar. 
  9, 
  

  

  stance 
  the 
  interval 
  was 
  great, 
  and 
  involved 
  the 
  occurrence 
  of 
  many 
  

   lithological 
  changes, 
  and 
  the 
  appearance 
  of 
  many 
  successive 
  genera- 
  

   tions 
  of 
  living 
  creatures, 
  about 
  the 
  site 
  of 
  the 
  blank. 
  

  

  M. 
  Bureau*, 
  in 
  the 
  course 
  of 
  some 
  interesting 
  observations 
  on 
  

   the 
  geology 
  of 
  the 
  Upper 
  Loire, 
  reports 
  the 
  conformable 
  junction 
  

   there 
  of 
  Devonian 
  with 
  Azoic 
  rocks, 
  and 
  with 
  the 
  granite 
  of 
  La 
  

   Vendee, 
  both 
  seemingly 
  pre- 
  Silurian. 
  

  

  The 
  little 
  we 
  know 
  of 
  the 
  Devonian 
  formation 
  of 
  Ireland 
  appears 
  

   to 
  promise 
  the 
  discovery 
  of 
  curious 
  phenomena. 
  Mr. 
  Godwin-Austen 
  

   considers 
  much 
  of 
  it 
  to 
  be 
  a 
  fluvio-lacustrine 
  deposit, 
  and 
  that 
  it 
  was 
  

   a 
  terrestrial 
  surface 
  anterior 
  to 
  the 
  oldest 
  sediment 
  of 
  the 
  Car- 
  

   boniferous 
  period. 
  It 
  lies, 
  we 
  must 
  not 
  forget 
  to 
  say, 
  on 
  Lower 
  

   Silurian, 
  and 
  therefore 
  marks 
  the 
  existence 
  of 
  a 
  wide 
  gap. 
  

  

  Mr. 
  Tate 
  found, 
  in 
  the 
  Lammermuir 
  Hills 
  of 
  the 
  south 
  of 
  Scot- 
  

   land, 
  Carboniferous 
  rocks 
  overlying 
  Old 
  Red 
  Sandstone 
  conformably 
  ; 
  

   and 
  then 
  follows 
  downwards 
  a 
  great 
  blank, 
  the 
  Devonian 
  being 
  in 
  

   unconformable 
  contact 
  with 
  the 
  so-called 
  Cambrian 
  rocks 
  f. 
  

  

  The 
  space 
  allotted 
  to 
  this 
  subject 
  will 
  allow 
  me 
  merely 
  to 
  men- 
  

   tion 
  that 
  seventy-eight 
  highly 
  suggestive 
  eases 
  have 
  been 
  brought 
  

   forward 
  by 
  Mr. 
  John 
  Kelly 
  i, 
  in 
  which 
  the 
  Old 
  Red 
  Sandstone 
  of 
  

   Ireland 
  rests 
  upon 
  beds 
  belonging 
  to 
  thirteen 
  different 
  epochs 
  ; 
  and 
  

   forty-eight 
  times 
  on 
  clay-slate 
  and 
  mica-slate. 
  

  

  9. 
  With 
  a 
  Silurian 
  Hoof. 
  — 
  No 
  inhabitants 
  of 
  dry 
  land 
  have 
  as 
  

   yet 
  been 
  found 
  in 
  the 
  sediments 
  of 
  this 
  epoch, 
  except 
  some 
  spores 
  

   and 
  fragments 
  of 
  low-classed 
  Land-plants. 
  Prof. 
  Edward 
  Forbes's 
  

   dredgings, 
  however, 
  have 
  shown 
  that 
  this 
  fact 
  may 
  lead 
  to 
  fallacious 
  

   conclusions 
  ; 
  and 
  our 
  Government 
  surveyors 
  § 
  not 
  very 
  long 
  ago 
  

   determined 
  that 
  land 
  did 
  exist 
  in 
  Shropshire 
  at 
  this 
  time 
  ; 
  and 
  they 
  

   have 
  begun 
  to 
  trace 
  the 
  boundaries 
  of 
  a 
  Silurian 
  sea-shore. 
  

  

  Potsdam 
  Sandstone 
  (Primordial) 
  must 
  have 
  been 
  frequently 
  above 
  

   the 
  reach 
  of 
  wave-action, 
  as 
  we 
  learn 
  from 
  the 
  tracks 
  of 
  large 
  Crus- 
  

   taceans, 
  which 
  may 
  almost 
  be 
  said 
  to 
  be 
  common 
  near 
  Perth, 
  in 
  

   Upper 
  Canada, 
  and 
  a 
  few 
  miles 
  west 
  of 
  Montreal. 
  

  

  The 
  multitudes 
  of 
  large 
  Coprolites 
  found 
  about 
  the 
  base 
  of 
  the 
  

   Silurian 
  strata 
  for 
  several 
  thousand 
  square 
  miles 
  of 
  the 
  lower 
  part 
  

   of 
  the 
  Yalley 
  of 
  the 
  Ottawa 
  lead 
  to 
  a 
  like 
  belief. 
  The 
  districts 
  

   join, 
  and 
  are 
  nearly 
  the 
  same. 
  

  

  The 
  Silurian 
  formation, 
  in 
  all 
  respects 
  so 
  instructive, 
  behaves 
  like 
  

   those 
  already 
  reviewed. 
  The 
  remark 
  of 
  Prof. 
  John 
  Phillips 
  ||, 
  that 
  

   no 
  district 
  yet 
  discovered 
  exhibits 
  the 
  Silurian 
  deposits 
  in 
  their 
  

   full 
  development, 
  is 
  perfectly 
  true. 
  Abounding 
  in 
  blanks, 
  its 
  

   lost 
  parts 
  are 
  innumerable, 
  as 
  Sir 
  R. 
  I. 
  Murchison 
  % 
  has 
  shown 
  in 
  

   profuse 
  detail. 
  

  

  A 
  few 
  distinct 
  and 
  authentic 
  cases 
  will 
  now 
  be 
  produced, 
  and 
  

   references 
  to 
  others 
  will 
  be 
  found 
  in 
  a 
  foot-note. 
  

  

  * 
  Bull. 
  Soc. 
  Geol. 
  France, 
  2 
  e 
  serie, 
  vol. 
  xvii. 
  p. 
  789. 
  

  

  t 
  Geologist, 
  vol. 
  iii. 
  p. 
  240. 
  t 
  Journ. 
  Geol. 
  Soc. 
  Dublin, 
  vol. 
  vii. 
  p. 
  122. 
  

  

  § 
  Lyell, 
  Quart. 
  Journ. 
  Geol. 
  Soc. 
  vol. 
  vii. 
  p. 
  liii. 
  

   || 
  Mem. 
  Geol. 
  Surv. 
  Great 
  Britain, 
  vol. 
  ii. 
  p. 
  217. 
  

  

  •([ 
  Siluria, 
  2nd 
  edit. 
  p. 
  Ill 
  ; 
  and 
  Murchison 
  and 
  Morris, 
  Quart. 
  Journ. 
  Geol. 
  

   Soc. 
  vol. 
  xi. 
  p. 
  440. 
  

  

  