﻿J. 
  W. 
  JEDD 
  ON 
  THE 
  SECONDARY 
  ROCKS 
  OE 
  SCOTLAND. 
  221 
  

  

  15. 
  Connexion 
  between 
  the 
  Tertiary 
  Volcanoes 
  of 
  the 
  Hebrides 
  and 
  those 
  

  

  of 
  other 
  districts. 
  

  

  16. 
  General 
  conclusions 
  from 
  the 
  relations 
  of 
  the 
  Volcanic 
  and 
  Plutonic 
  

  

  rocks 
  of 
  the 
  Tertiary 
  period. 
  

  

  III. 
  The 
  Newer-Palreozoic 
  Volcanoes. 
  

  

  1. 
  Lavas 
  of 
  Lorn 
  and 
  the 
  adjacent 
  islands. 
  

  

  2. 
  Characters 
  of 
  the 
  Volcanic 
  rocks 
  of 
  Lorn. 
  

  

  3. 
  Relations 
  of 
  the 
  Volcanic 
  rocks 
  of 
  Lorn. 
  

  

  4. 
  Succession 
  of 
  rocks 
  in 
  Lorn. 
  

  

  5. 
  Conditions 
  under 
  which 
  the 
  Volcanic 
  series 
  of 
  Lorn 
  was 
  deposited. 
  

  

  6. 
  Age 
  of 
  the 
  Volcanic 
  series 
  of 
  Lorn. 
  

  

  7. 
  The 
  Newer-Paheozoic 
  lavas 
  of 
  the 
  Lowlands 
  of 
  Scotland. 
  

  

  8. 
  The 
  Eruptive 
  masses 
  of 
  the 
  Grampian 
  mountains. 
  

  

  9. 
  Relations 
  of 
  the 
  igneous 
  rocks 
  of 
  Beinn 
  Nevis 
  and 
  Glencoe. 
  

  

  10. 
  Physical 
  Features 
  of 
  Northern 
  Scotland 
  during 
  the 
  Newer-Paheozoic 
  

   periods. 
  

  

  IV. 
  Conclusion. 
  

  

  1. 
  Comparison 
  of 
  the 
  two 
  great 
  periods 
  of 
  Volcanic 
  activity 
  in 
  Scotland. 
  

  

  2. 
  Influence 
  of 
  Volcanic 
  action 
  in 
  determining 
  the 
  Characters 
  and 
  Rela- 
  

  

  tions 
  of 
  the 
  Secondary 
  rocks 
  of 
  Scotland. 
  

  

  3. 
  The 
  " 
  Geological 
  Record 
  " 
  in 
  the 
  Highlands. 
  

  

  4. 
  Light 
  thrown 
  upon 
  some 
  problems 
  of 
  Physical 
  Geology 
  by 
  the 
  

   Volcanic 
  rocks 
  of 
  the 
  Highlands. 
  

  

  I. 
  Introduction. 
  

  

  For 
  the 
  preservation 
  of 
  the 
  most 
  valuable 
  illustrations 
  of 
  the 
  in- 
  

   stitutions, 
  manners, 
  and 
  arts 
  of 
  Ancient 
  Rome, 
  the 
  archaeologist 
  is 
  

   indebted 
  to 
  the 
  action 
  of 
  a 
  volcano 
  : 
  the 
  relics 
  of 
  Pompeii 
  have 
  

   survived 
  in 
  consequence 
  of 
  being 
  buried 
  under 
  the 
  ejections 
  of 
  

   Vesuvius. 
  To 
  a 
  similar 
  agency, 
  operating 
  at 
  a 
  distant 
  epoch 
  and 
  

   on 
  a 
  far 
  grander 
  scale, 
  the 
  geologist 
  owes 
  the 
  escape 
  from 
  destruction, 
  

   in 
  the 
  Western 
  Isles 
  of 
  Scotland, 
  of 
  most 
  wonderful 
  monuments 
  of 
  

   physical 
  change 
  and 
  highly 
  interesting 
  records 
  of 
  life-history 
  during 
  

   the 
  Secondary 
  periods 
  ; 
  for 
  such, 
  indeed, 
  are 
  those 
  remarkably 
  pre- 
  

   served 
  fragments 
  of 
  sedimentary 
  rocks 
  which 
  it 
  is 
  the 
  object 
  of 
  this 
  

   memoir 
  to 
  describe. 
  

  

  As 
  he 
  prosecutes 
  an 
  examination 
  and 
  comparison 
  of 
  all 
  the 
  cir- 
  

   cumstances 
  under 
  which 
  the 
  scattered 
  relics 
  of 
  the 
  Secondary 
  

   formations 
  present 
  themselves 
  in 
  the 
  West 
  of 
  Scotland, 
  the 
  geologist 
  

   will 
  be 
  again 
  and 
  again 
  impressed 
  by 
  the 
  extent 
  of 
  the 
  protective 
  

   influence 
  which 
  the 
  vast 
  masses 
  of 
  Tertiary 
  lava 
  have 
  evidently 
  

   exerted 
  upon 
  the 
  subjacent 
  stratified 
  rocks. 
  And 
  when 
  he 
  has 
  

   concluded 
  that 
  survey, 
  he 
  can 
  scarcely 
  have 
  failed 
  to 
  arrive 
  at 
  the 
  

   conclusion 
  that, 
  but 
  for 
  this 
  protective 
  influence, 
  every 
  vestige 
  of 
  

   the 
  Mesozoic 
  deposits 
  in 
  the 
  district 
  must 
  have 
  been 
  inevitably 
  

   swept 
  away 
  by 
  denudation*. 
  

  

  * 
  Those 
  familiar 
  with 
  the 
  geology 
  of 
  Central 
  France 
  will 
  at 
  once 
  recall 
  the 
  

   manner 
  in 
  which 
  the 
  sheets 
  of 
  basaltic 
  lava 
  capping 
  the 
  great 
  plateaux 
  have, 
  in 
  

   so 
  many 
  cases, 
  secured 
  the 
  preservation 
  of 
  masses 
  of 
  the 
  lacustrine 
  strata 
  on 
  

   which 
  they 
  rest, 
  every 
  trace 
  of 
  which 
  must 
  otherwise 
  have 
  been 
  swept 
  away 
  by 
  

   denuding 
  forces. 
  ( 
  Vide 
  Scrope's 
  ' 
  Geology 
  and 
  Extinct 
  Volcanos 
  of 
  Central 
  

   France,' 
  p. 
  7 
  &c.) 
  

  

  