﻿2 
  20 
  J. 
  "W. 
  JTJDD 
  ON 
  THE 
  SECONDARY 
  ROCKS 
  OF 
  SCOTLAND. 
  

  

  23. 
  The 
  Secondary 
  Eocks 
  of 
  Scotland. 
  Second 
  Paper*. 
  On 
  the 
  

   Ancient 
  Volcanoes 
  of 
  the 
  Highlands 
  and 
  the 
  Relations 
  of 
  their 
  

   Products 
  to 
  the 
  Mesozoic 
  Strata. 
  By 
  John 
  W. 
  Jttdd, 
  Esq., 
  F.G.S. 
  

   (Eead 
  January 
  21, 
  1874.) 
  

  

  [Plates 
  XXII. 
  & 
  XXIII.] 
  

  

  Contents. 
  

   I. 
  Introduction. 
  

  

  1. 
  History 
  of 
  Previous 
  Opinion 
  on 
  the 
  subject. 
  

  

  2. 
  Volcanic 
  Origin 
  of 
  the 
  rocks 
  constituting 
  the 
  great 
  plateaux 
  of 
  the 
  

  

  Hebrides 
  and 
  the 
  North 
  of 
  Ireland. 
  

  

  3. 
  Subaerial 
  Origin 
  of 
  these 
  old 
  Volcanic 
  rocks. 
  

  

  4. 
  Evidences 
  of 
  the 
  Former 
  Existence 
  of 
  great 
  Volcanic 
  mountains 
  

  

  in 
  the 
  district. 
  

  

  II. 
  The 
  Tertiary 
  Volcanoes. 
  

  

  1. 
  Classification 
  of 
  the 
  Tertiary 
  Volcanic 
  rocks. 
  

  

  2. 
  Nature 
  and 
  origin 
  of 
  the 
  great 
  Volcanic 
  rock-masses 
  : 
  — 
  Lavas, 
  Intru- 
  

  

  sive 
  masses, 
  Volcanic 
  agglomerates 
  and 
  Volcanic 
  breccias. 
  

  

  3. 
  Relations 
  of 
  the 
  Volcanic 
  rocks 
  to 
  one 
  another 
  and 
  to 
  the 
  oMer 
  

  

  deposits 
  in 
  the 
  island 
  of 
  Mull. 
  

  

  4. 
  Sections 
  illustrating 
  the 
  structure 
  of 
  the 
  island 
  of 
  Mull; 
  — 
  Beinn 
  

  

  Greig, 
  Beinn 
  Uaig, 
  Craig 
  Craggen, 
  Beinn 
  More. 
  

  

  5. 
  Proofs 
  that 
  the 
  central 
  mountain-group 
  of 
  Mull 
  constitutes 
  the 
  relic 
  

  

  of 
  a 
  great 
  volcano. 
  

  

  6. 
  The 
  Volcano 
  of 
  Ardnamurchan. 
  

  

  7. 
  The 
  Volcano 
  of 
  Rum. 
  

  

  8. 
  The 
  Volcano 
  of 
  Skye. 
  

  

  9. 
  The 
  Volcano 
  of 
  St. 
  Kilda. 
  

  

  10. 
  Comparison 
  of 
  the 
  great 
  Tertiary 
  Volcanoes. 
  

  

  11. 
  Dimensions 
  of 
  the 
  great 
  Tertiary 
  Volcanoes. 
  

  

  12. 
  Series 
  of 
  later 
  Volcanic 
  eruptions 
  in 
  the 
  Hebrides, 
  resulting 
  in 
  the 
  

  

  formation 
  of 
  " 
  Puys." 
  

  

  13. 
  Subterranean 
  Phenomena 
  of 
  the 
  Tertiary 
  Volcanoes. 
  

  

  14. 
  .Ages 
  of 
  the 
  several 
  Volcanic 
  outbursts 
  already 
  described. 
  

  

  * 
  In 
  the 
  first 
  published 
  paper 
  of 
  this 
  series 
  (vide 
  Quart. 
  Journ. 
  Geol. 
  Sec. 
  

   vol. 
  xxix. 
  p. 
  97) 
  I 
  found 
  it 
  possible, 
  in 
  a 
  single 
  communication, 
  not 
  only 
  to 
  

   discuss 
  the 
  nature 
  and 
  origin 
  of 
  the 
  remarkable 
  physical 
  relations 
  of 
  the 
  vestiges 
  

   of 
  the 
  Secondary 
  strata 
  on 
  the 
  east 
  coast 
  of 
  Scotland, 
  but 
  also 
  to 
  reconstruct 
  

   from 
  them 
  the 
  history 
  of 
  the 
  several 
  Mesozoic 
  periods 
  as 
  exemplified 
  in 
  that 
  

   district. 
  This, 
  however, 
  was 
  only 
  accomplished 
  by 
  extending 
  the 
  paper 
  to 
  a 
  

   somewhat 
  unusual 
  length 
  ; 
  and 
  in 
  dealing 
  with 
  the 
  strata 
  of 
  the 
  same 
  age 
  on 
  

   the 
  western 
  coast, 
  I 
  have 
  found 
  it 
  impossible, 
  such 
  is 
  the' 
  complication 
  of 
  the 
  

   questions 
  involved 
  in 
  their 
  study, 
  to 
  deal 
  with 
  both 
  branches 
  of 
  my 
  subject 
  in 
  

   a 
  single 
  paper. 
  Consequently 
  I 
  have 
  confined 
  myself, 
  in 
  the 
  present 
  commu- 
  

   nication, 
  to 
  a 
  description 
  of 
  the 
  positions 
  and 
  relations 
  of 
  the 
  fragments 
  of 
  

   Secondary 
  strata, 
  and 
  a 
  discussion 
  of 
  the 
  causes 
  to 
  which 
  these 
  are 
  due. 
  In 
  

   a 
  third 
  paper, 
  which 
  is 
  already 
  in 
  an 
  advanced 
  stage 
  of 
  preparation, 
  I 
  propose 
  

   to 
  illustrate 
  the 
  succession 
  of 
  geological 
  events 
  in 
  the 
  Western 
  Highlands 
  

   during 
  the 
  Mesozoic 
  periods 
  ; 
  while 
  in 
  a 
  fourth 
  paper 
  I 
  anticipate 
  being 
  able 
  

   to 
  conclude 
  the 
  account 
  of 
  my 
  studies 
  of 
  these 
  rocks 
  by 
  an 
  endeavour 
  to 
  deal 
  

   with 
  those 
  problems 
  of 
  ancient 
  physical 
  geography 
  and 
  general 
  palaeontology 
  

   for 
  the 
  solution 
  of 
  which 
  these 
  remarkable 
  fragments 
  of 
  Secondary 
  strata 
  sup- 
  

   ply 
  such 
  valuable 
  materials. 
  

  

  