﻿J. 
  W. 
  JUDD 
  ON 
  THE 
  SECONDARY 
  ROCKS 
  OF 
  SCOTLAND. 
  275 
  

  

  To 
  those 
  familiar 
  only 
  with 
  the 
  English 
  representatives 
  of 
  the 
  

   three 
  great 
  Tertiary 
  periods, 
  the 
  Eocene 
  sands, 
  marls, 
  and 
  clays, 
  of 
  

   the 
  London 
  and 
  Hainpsbire 
  basins, 
  the 
  Miocene 
  lignitiferous 
  beds 
  

   of 
  Bovey 
  Tracey, 
  and 
  the 
  insignificant 
  Pliocene 
  deposits 
  of 
  the 
  Crags, 
  

   the 
  evidences 
  of 
  such 
  enormous 
  physical 
  changes, 
  as 
  we 
  have 
  shown 
  

   must 
  have 
  taken 
  place 
  in 
  the 
  north-western 
  portion 
  of 
  these 
  islands 
  

   during 
  the 
  same 
  periods, 
  will 
  indeed 
  appear 
  startling. 
  But 
  to 
  re- 
  

   move 
  any 
  feelings 
  of 
  difficulty 
  or 
  doubt 
  which 
  may 
  have 
  their 
  source 
  

   in 
  such 
  comparisons, 
  it 
  is 
  only 
  necessary 
  to 
  refer 
  to 
  the 
  well-ascer- 
  

   tained 
  facts 
  of 
  the 
  geology 
  of 
  the 
  Alps, 
  where 
  events 
  on 
  even 
  a 
  

   grander 
  scale 
  than 
  those 
  which 
  we 
  have 
  described, 
  can 
  be 
  shown 
  to 
  

   have 
  taken 
  place 
  during 
  the 
  same 
  periods. 
  

  

  15. 
  Connexion 
  between 
  the 
  Tertiary 
  Volcanoes 
  of 
  the 
  Hebrides 
  and 
  

   those 
  of 
  other 
  districts. 
  — 
  It 
  would 
  be 
  foreign 
  to 
  the 
  objects 
  of 
  the 
  

   present 
  memoir 
  to 
  enter 
  upon 
  a 
  discussion 
  of 
  this 
  most 
  interesting 
  

   question. 
  I 
  shall 
  therefore 
  only 
  state 
  that, 
  while 
  we 
  have 
  the 
  

   clearest 
  proofs 
  of 
  the 
  contemporaneity 
  of 
  the 
  basalts 
  of 
  Antrim 
  with 
  

   those 
  of 
  the 
  Inner 
  Hebrides, 
  we 
  have 
  also 
  strong 
  grounds 
  for 
  regard- 
  

   ing 
  the 
  granites 
  of 
  Arran 
  and 
  the 
  Mourne 
  Mountains 
  as 
  having 
  

   been 
  erupted 
  during 
  the 
  same 
  period 
  with 
  those 
  of 
  Skye, 
  Mull, 
  Bum, 
  

   &c* 
  Thus 
  we 
  are 
  led 
  to 
  the 
  conclusion 
  that 
  along 
  a 
  line 
  stretching 
  

   at 
  least 
  400 
  miles 
  from 
  north 
  to 
  south, 
  in 
  the 
  north-western 
  part 
  of 
  the 
  

   British 
  archipelago, 
  there 
  rose, 
  during 
  a 
  great 
  portion 
  of 
  the 
  Tertiary 
  

   period, 
  a 
  chain 
  of 
  volcanoes 
  in 
  a 
  state 
  of 
  violent 
  but 
  intermittent 
  erup- 
  

   tion. 
  But 
  continuing 
  this 
  line 
  to 
  the 
  northwards, 
  we 
  find 
  the 
  proofs 
  

   of 
  volcanic 
  action 
  during 
  part 
  of 
  the 
  Tertiary 
  period 
  (and 
  in 
  some 
  

   cases, 
  at 
  least, 
  this 
  action 
  has 
  not 
  yet 
  become 
  extinct) 
  in 
  the 
  Faroe 
  

   Islands, 
  Iceland, 
  Jan 
  Meyen, 
  and 
  Greenland. 
  And 
  southward 
  the 
  

   same 
  line 
  of 
  volcanic 
  vents 
  is 
  continued 
  in 
  Central 
  France, 
  the 
  Iberian 
  

   peninsula, 
  the 
  Azores, 
  Madeira, 
  the 
  Canaries, 
  Cape- 
  Verde 
  Islands, 
  

   Ascension, 
  St. 
  Helena, 
  and 
  Tristan 
  d'Acunha. 
  

  

  When 
  we 
  remember 
  the 
  proofs 
  of 
  the 
  existence 
  of 
  widely 
  spread 
  

   terrestrial 
  conditions 
  during 
  the 
  Miocene 
  epoch, 
  and 
  the 
  interesting 
  

   facts 
  concerning 
  the 
  distribution 
  of 
  existing 
  terrestrial 
  species, 
  made 
  

   known 
  to 
  us 
  by 
  the 
  labours 
  of 
  Edward 
  Forbes, 
  Unger, 
  Heer, 
  and 
  

   others, 
  we 
  may 
  well 
  be 
  prepared 
  to 
  regard 
  these 
  isolated 
  masses 
  of 
  

   volcanic 
  rocks, 
  as 
  has 
  been 
  suggested 
  by 
  Professor 
  Nordenskiold, 
  as 
  

   portions 
  of 
  a 
  great 
  ridge 
  now 
  for 
  the 
  most 
  part 
  submerged 
  beneath 
  

   the 
  sea-level 
  and 
  constituting 
  a 
  boundary 
  to 
  the 
  great 
  eastern 
  conti- 
  

   nent, 
  similar 
  to 
  that 
  which 
  the 
  Andes, 
  Cordilleras, 
  and 
  Bocky 
  Moun- 
  

  

  faunas 
  of 
  certain 
  deposits 
  with 
  those 
  of 
  recent 
  seas, 
  I 
  am 
  actuated 
  by 
  a 
  feeling 
  

   of 
  the 
  necessity 
  of 
  such 
  a 
  comparison 
  to 
  a 
  due 
  appreciation 
  of 
  the 
  subject, 
  

   rather 
  than 
  by 
  a 
  belief 
  in 
  the 
  possibility 
  of 
  establishing 
  any 
  thing 
  like 
  actual 
  

   contemporaneity 
  between 
  divisions 
  based 
  respectively 
  on 
  purely 
  palaontological 
  

   and 
  physical 
  evidence, 
  both 
  of 
  which 
  series 
  of 
  divisions, 
  moreover, 
  are 
  incapa- 
  

   ble 
  of 
  very 
  exact 
  definition 
  and 
  limitation. 
  

  

  * 
  My 
  friend, 
  Mr. 
  Thomas 
  Davies, 
  has 
  called 
  my 
  attention 
  to 
  the 
  fact 
  that 
  the 
  

   granite 
  of 
  Lundy 
  Island 
  offers 
  peculiarities 
  of 
  structure 
  strikingly 
  similar 
  to 
  

   those 
  presented 
  by 
  the 
  granites 
  of 
  the 
  Mourne 
  Mountains, 
  Arran, 
  and 
  the 
  

   Northern 
  Hebrides. 
  It 
  is 
  possible, 
  therefore, 
  that 
  in 
  Lundy 
  Island 
  we 
  have 
  

   relies 
  of 
  another 
  of 
  the 
  centres 
  of 
  volcanic 
  action 
  during 
  the 
  Tertiary 
  period. 
  

  

  