﻿DEVCmO-SILrPvLO" 
  rOE3IATI03f. 
  207 
  

  

  from 
  the 
  statement 
  on 
  the 
  subject 
  by 
  Mr. 
  Etheridge 
  in 
  his 
  recent 
  

   Presidential 
  Address 
  *. 
  

  

  I 
  confess 
  to 
  a 
  feeling 
  bordering 
  on 
  remorse 
  in 
  throwing 
  a 
  doubt 
  

   on 
  the 
  propriety 
  of 
  the 
  name 
  which 
  has 
  been 
  associated 
  with 
  these 
  

   beds 
  by 
  the 
  Scottish 
  geologists, 
  including 
  the 
  honoured 
  names 
  of 
  

   Boue, 
  Macculloch, 
  Hugh 
  Miller, 
  and 
  those 
  of 
  more 
  recent 
  times 
  : 
  

   and 
  I 
  almost 
  despair 
  of 
  persuading 
  my 
  Scottish 
  contemporaries 
  that 
  

   the 
  only 
  true 
  Old 
  Red 
  Sandstone 
  to 
  which 
  their 
  country 
  can 
  lay 
  

   claim 
  is 
  the 
  comparatively 
  insignificant 
  series 
  of 
  sandstones 
  and 
  

   conglomerates 
  which 
  (in 
  geological 
  sequence) 
  unconformably 
  over- 
  

   lies 
  the 
  great 
  ichthyic 
  formation 
  of 
  " 
  Lake 
  Orcadie," 
  or 
  " 
  Lake 
  Cale- 
  

   donia," 
  and 
  of 
  " 
  Lake 
  Cheviot," 
  and 
  underlies 
  the 
  Calciferous 
  Sand- 
  

   stone 
  of 
  the 
  Lower 
  Carboniferous 
  series. 
  

  

  It 
  is 
  scarcely 
  necessary 
  for 
  me 
  to 
  do 
  more 
  than 
  allude 
  to 
  the 
  great 
  

   Scottish 
  formation, 
  so 
  well 
  described 
  on 
  a 
  recent 
  occasion 
  by 
  Pro- 
  

   fessor 
  Geikie 
  as 
  occupying 
  several 
  distinct 
  old 
  lake-basins, 
  sur- 
  

   rounded 
  by 
  Silurian 
  or 
  Metamorphic 
  rocks, 
  and 
  attaining 
  in 
  Caith- 
  

   ness 
  an 
  estimated 
  thickness 
  of 
  16,200 
  feet, 
  with 
  its 
  magnificent 
  

   assemblage 
  of 
  fossil 
  fish, 
  amounting 
  to 
  about 
  18 
  genera 
  and 
  60 
  

   species, 
  together 
  with 
  Crustaceans 
  and 
  plants. 
  This 
  ichthyic 
  fauna 
  

   redeems 
  the 
  great 
  Devono-Silurian 
  group 
  from 
  the 
  charge 
  of 
  well-nigh 
  

   utter 
  barrenness. 
  Of 
  the 
  character 
  of 
  the 
  Molluscan 
  fauna 
  we 
  have 
  no 
  

   evidence 
  ; 
  but 
  if 
  (as 
  may 
  be 
  supposed) 
  the 
  Devonian 
  fauna 
  was 
  the 
  

   lineal 
  descendant 
  of 
  the 
  Upper 
  Silurian, 
  to 
  which, 
  however 
  (as 
  Mr. 
  

   Etheridge 
  has 
  shown), 
  it 
  bears 
  very 
  little 
  specific 
  resemblance, 
  then 
  

   the 
  fauna 
  of 
  the 
  Devono-Silurian 
  period 
  must 
  have 
  had 
  a 
  fades 
  of 
  an 
  

   intermediate 
  character 
  between 
  the 
  Upper 
  Silurian 
  on 
  the 
  one 
  hand 
  

   and 
  the 
  Devonian 
  on 
  the 
  other. 
  This 
  fauna 
  must 
  have 
  occupied 
  

   some 
  pelagic 
  region 
  outside 
  the 
  limits 
  of 
  the 
  British 
  Isles 
  and 
  of 
  

   Western 
  Europe. 
  

  

  Summary. 
  — 
  To 
  briefly 
  recapitulate, 
  I 
  include, 
  therefore, 
  under 
  

   the 
  name 
  " 
  Devono-Silurian 
  " 
  the 
  following 
  : 
  — 
  

  

  (1) 
  The 
  grits, 
  conglomerates, 
  and 
  slates 
  lying 
  at 
  the 
  base 
  of 
  the 
  

   Lower 
  Devonian 
  series 
  of 
  Belgium, 
  &c. 
  (" 
  systeme 
  Gedinnien"). 
  

  

  (2) 
  The 
  Eoreland 
  Grits 
  and 
  Slates 
  of 
  Devonshire. 
  

  

  (3) 
  The 
  " 
  Passage-beds 
  " 
  of 
  South 
  Wales, 
  Hereford, 
  &c, 
  including 
  

   the 
  Downton 
  Sandstone 
  and 
  the 
  beds 
  of 
  the 
  ridge 
  of 
  the 
  

   Trichrag. 
  

  

  (4) 
  The 
  Dingle 
  and 
  Glengariff 
  Grits 
  and 
  Slates 
  of 
  the 
  south 
  of 
  

   Ireland. 
  

  

  (5) 
  The 
  Pintona-beds 
  of 
  the 
  north 
  of 
  Ireland. 
  

  

  (6) 
  The 
  so-called 
  " 
  Lower 
  Old 
  Red 
  Sandstone" 
  of 
  Scotland, 
  be- 
  

   longing 
  to 
  several 
  basins. 
  

  

  * 
  The 
  President 
  of 
  the 
  Geological 
  Society 
  states 
  as 
  follows 
  : 
  — 
  "If 
  Professor 
  

   Geikie 
  is 
  right 
  iu 
  saying 
  that 
  the 
  Scotch 
  Old 
  Red 
  Sandstone 
  represents 
  the 
  

   Irish 
  Glengariff 
  beds, 
  then 
  Professor 
  Hull 
  may 
  be 
  right 
  in 
  concluding 
  that 
  the 
  

   Scotch 
  beds 
  are 
  the 
  lacustrine 
  equivalents 
  in 
  time 
  of 
  the 
  marine 
  uppermost 
  

   Silurian 
  strata." 
  — 
  Op. 
  cit. 
  p. 
  197. 
  

  

  