﻿378 
  THE 
  LATE 
  MR. 
  A. 
  CHAHPERNOWXE 
  ON 
  THE 
  

  

  a 
  condition 
  for 
  publication. 
  But 
  it 
  is 
  imperfect, 
  and 
  no 
  materials 
  

   remained 
  from 
  which 
  it 
  could 
  be 
  completed 
  ; 
  still 
  it 
  was 
  too 
  valuable 
  

   a 
  piece 
  of 
  work 
  to 
  leave 
  unpublished. 
  

  

  There 
  were 
  two 
  principal 
  points 
  in 
  this 
  last 
  work 
  of 
  Mr. 
  Cham- 
  

   pernowne 
  : 
  — 
  (1) 
  the 
  non-intrusive 
  character 
  of 
  the 
  beds 
  in 
  question 
  ; 
  

   (2) 
  their 
  geological 
  horizon, 
  regarding 
  which, 
  though, 
  owing 
  to 
  the 
  

   faulted 
  nature 
  of 
  the 
  country, 
  it 
  is 
  rather 
  obscure, 
  Mr. 
  Champer- 
  

   nowne's 
  surmises 
  may 
  turn 
  out 
  to 
  be 
  correct. 
  There 
  was 
  no 
  allu- 
  

   sion 
  in 
  the 
  paper 
  to 
  the 
  compression 
  and 
  shearing 
  the 
  rocks 
  had 
  

   undergone, 
  to 
  which 
  he 
  (Dr. 
  Geikie) 
  attributed 
  much 
  of 
  the 
  schistose 
  

   structure 
  both 
  of 
  the 
  sedimentary 
  and 
  igneous 
  rocks 
  of 
  the 
  region. 
  

   The 
  flaky 
  beds 
  of 
  which 
  the 
  Author 
  speaks 
  can 
  be 
  traced 
  into 
  

   the 
  more 
  massive 
  rocks. 
  The 
  flattening 
  -out 
  of 
  the 
  amygdaloids 
  

   was 
  a 
  striking 
  proof 
  of 
  this 
  mechanical 
  deformation. 
  

  

  Mr. 
  Htjtlet 
  referred 
  to 
  the 
  general 
  soundness 
  of 
  Mr. 
  Champer- 
  

   nowne's 
  conclusions 
  ; 
  there 
  were 
  some 
  interesting 
  points 
  in 
  con- 
  

   nexion 
  with 
  these 
  lavas. 
  He 
  had 
  himself 
  noticed 
  important 
  differences 
  

   in 
  the 
  volcanic 
  beds 
  on 
  the 
  east 
  and 
  those 
  on 
  the 
  west 
  side 
  of 
  

   Dartmoor 
  respectively. 
  On 
  the 
  east 
  they 
  were 
  mostly 
  porphyrites, 
  

   on 
  the 
  west 
  schistose 
  lavas 
  and 
  basalts, 
  the 
  schistose 
  beds 
  being 
  

   very 
  characteristic 
  of 
  the 
  Brent-Tor 
  district, 
  of 
  which 
  he 
  considered 
  

   the 
  Saltash 
  lavas 
  were 
  a 
  continuation. 
  Xo 
  perfectly 
  satisfactory 
  

   explanation 
  of 
  the 
  causes 
  of 
  this 
  schistose 
  character 
  had 
  yet 
  been 
  

   given. 
  He 
  had 
  not 
  hitherto 
  observed 
  any 
  mechanical 
  deformation 
  

   of 
  the 
  amygdaloids 
  in 
  the 
  schistose 
  lavas, 
  such 
  as 
  those 
  of 
  Churl- 
  

   hanger, 
  and 
  this, 
  he 
  thought, 
  militated 
  against 
  the 
  assumption 
  that 
  

   the 
  schistose 
  structure 
  was 
  due 
  to 
  shearing. 
  He 
  referred 
  to 
  the 
  

   boundary 
  between 
  the 
  Carboniferous 
  and 
  Devonian 
  as 
  having 
  

   been 
  drawn 
  along 
  belts 
  of 
  igneous 
  rock, 
  which 
  were, 
  in 
  point 
  of 
  fact, 
  

   repetitions 
  of 
  the 
  same 
  bed. 
  He 
  referred 
  to 
  the 
  new 
  line 
  of 
  railway 
  

   as 
  likely 
  to 
  throw 
  some 
  light 
  upon 
  the 
  district 
  west 
  of 
  Dartmoor. 
  

  

  Dr. 
  Hatch 
  spoke 
  of 
  the 
  rocks 
  from 
  Ashprington 
  as 
  tuffs 
  and 
  

   diabases, 
  mostly 
  aphanitic, 
  but 
  sometimes 
  porphyritic. 
  They 
  were 
  

   not 
  very 
  suitable 
  for 
  microscopic 
  examination, 
  owing 
  to 
  their 
  ad- 
  

   vanced 
  stage 
  of 
  decomposition, 
  the 
  felspars 
  being 
  turbid, 
  the 
  augite 
  

   having 
  mostly 
  passed 
  into 
  chlorite, 
  the 
  ilmenite 
  into 
  leucoxene, 
  and 
  

   there 
  being 
  an 
  abundance 
  of 
  calcite. 
  Where 
  at 
  all 
  fresh 
  there 
  were 
  

   traces 
  of 
  ophitic 
  structure. 
  In 
  some 
  cases 
  the 
  amygdaloidal 
  rocks 
  

   showed 
  traces 
  of 
  shearing. 
  The 
  tuffs 
  closely 
  resembled 
  the 
  " 
  Schal- 
  

   steins 
  " 
  of 
  Nassau 
  and 
  the 
  Hartz. 
  

  

  Mr. 
  "Worth 
  said 
  that 
  the 
  volcanic 
  series 
  had 
  occupied 
  much 
  of 
  

   his 
  attention, 
  and 
  that 
  practically 
  the 
  rocks 
  under 
  discussion 
  were 
  

   similar 
  to 
  those 
  in 
  the 
  neighbourhood 
  of 
  Plymouth. 
  He 
  differed 
  

   from 
  Mr. 
  Champernowne's 
  conclusion, 
  as 
  to 
  their 
  horizons, 
  especially 
  

   as 
  regards 
  the 
  Plymouth 
  district. 
  He 
  was 
  of 
  opinion 
  that 
  they 
  

   underlie 
  the 
  Plymouth 
  Limestone, 
  and 
  that 
  on 
  this 
  horizon 
  may 
  be 
  

   traced 
  the 
  beginnings 
  of 
  a 
  coral 
  reef. 
  

  

  He 
  referred 
  to 
  the 
  new 
  line 
  on 
  the 
  west 
  side 
  of 
  Dartmoor, 
  and 
  

   to 
  the 
  light 
  it 
  was 
  calculated 
  to 
  throw 
  upon 
  the 
  geology 
  of 
  the 
  

   district, 
  especially 
  in 
  reference 
  to 
  the 
  volcanic 
  rocks. 
  Alterations 
  

  

  