﻿

  AND 
  BANDED 
  CRYSTALLINE 
  EOCES 
  OF 
  TIIE 
  LIZARD. 
  543 
  

  

  differences 
  between 
  Prof. 
  Bonney 
  and 
  himself, 
  he 
  had 
  also 
  differed 
  

   from 
  both, 
  though 
  perhaps 
  agreeing 
  more 
  with 
  Prof. 
  Bonney. 
  The 
  

   paper 
  followed 
  one 
  read 
  at 
  a 
  previous 
  meeting, 
  where 
  foliation 
  was 
  

   actually 
  taken 
  as 
  evidence 
  of 
  deformation. 
  The 
  absence 
  of 
  mechani- 
  

   cal 
  crushing 
  in 
  the 
  crystals 
  of 
  a 
  rock 
  could 
  not, 
  he 
  believed, 
  be 
  taken 
  

   as 
  evidence 
  that 
  the 
  rock 
  was 
  not 
  due 
  to 
  the 
  deformation 
  of 
  a 
  pre- 
  

   existing 
  rock. 
  Referring 
  to 
  the 
  Scourie 
  dyke, 
  he 
  observed 
  that 
  

   it 
  yielded 
  absolute 
  proof 
  of 
  a 
  holo-crystalline 
  schist 
  produced 
  by 
  

   the 
  deformation 
  of 
  a 
  preexisting 
  crystalline 
  rock. 
  With 
  regard 
  

   to 
  the 
  Author's 
  speculations 
  as 
  to 
  the 
  banding 
  of 
  the 
  crystalline 
  

   schists 
  of 
  the 
  Lizard, 
  he 
  must 
  confess 
  that 
  he 
  was 
  unable 
  to 
  

   follow 
  them. 
  As 
  to 
  the 
  origin 
  of 
  the 
  series 
  as 
  a 
  whole, 
  he 
  wished 
  

   to 
  remain 
  neutral 
  for 
  the 
  present. 
  The 
  granulitic 
  group 
  supposed 
  

   by 
  Dr. 
  Bonney 
  to 
  be 
  a 
  sedimentary 
  series 
  is 
  considered 
  by 
  the 
  Author 
  

   to 
  be 
  sedimentary 
  with 
  intrusions. 
  He 
  thought 
  no 
  further 
  advance 
  

   could 
  be 
  made 
  on 
  this 
  point 
  until 
  the 
  supposed 
  two 
  series 
  had 
  been 
  

   mapped. 
  In 
  a 
  paper 
  he 
  had 
  written 
  elsewhere 
  on 
  the 
  origin 
  of 
  banded 
  

   gneisses, 
  he 
  had 
  referred 
  to 
  the 
  granulitic 
  series, 
  and 
  he 
  was 
  not 
  dis- 
  

   posed 
  to 
  modify 
  his 
  view 
  from 
  what 
  he 
  had 
  heard. 
  The 
  granitic 
  and 
  

   dioritic 
  rocks 
  of 
  the 
  series 
  exhibit 
  indubitable 
  igneous 
  relations 
  in 
  

   places, 
  whilst 
  in 
  other 
  places 
  they 
  occur 
  as 
  parts 
  of 
  a 
  banded 
  gneissic 
  

   series. 
  In 
  the 
  banded 
  rocks 
  there 
  are 
  appearances 
  strongly 
  sug- 
  

   gestive 
  of 
  fluxion, 
  and 
  he 
  had 
  proposed 
  that 
  the 
  banding 
  was 
  the 
  

   result 
  of 
  the 
  deformation 
  of 
  a 
  heterogeneous 
  mass 
  whether 
  before 
  

   or 
  after 
  consolidation, 
  and 
  had 
  illustrated 
  his 
  views 
  by 
  experi- 
  

   ments. 
  There 
  was 
  no 
  limit 
  to 
  the 
  fineness 
  of 
  the 
  banding 
  pro- 
  

   duced 
  by 
  deformation. 
  He 
  believed 
  that 
  when 
  the 
  truth 
  was 
  fully 
  

   out, 
  it 
  would 
  be 
  found 
  that 
  everyone 
  who 
  had 
  worked 
  at 
  the 
  

   district 
  had 
  contributed 
  towards 
  it. 
  

  

  Prof. 
  Bonney 
  had 
  examined 
  the 
  schists 
  at 
  an 
  unfortunate 
  epoch, 
  

   and 
  he 
  had 
  consequently 
  fallen 
  into 
  one 
  error. 
  Amongst 
  the 
  banded 
  

   series 
  occurred 
  porphyritic 
  felspar, 
  which 
  he 
  now 
  knew 
  was 
  usually 
  

   indicative 
  of 
  an 
  igneous 
  origin, 
  and 
  he 
  had 
  overlooked 
  several 
  

   masses 
  which 
  he 
  would 
  now 
  be 
  inclined 
  to 
  regard 
  as 
  igneous. 
  

   But 
  after 
  reexamination 
  he 
  was 
  by 
  no 
  means 
  clear 
  as 
  to 
  whether 
  the 
  

   general 
  metamorphic 
  origin 
  of 
  the 
  Lizard 
  rocks 
  can 
  be 
  given 
  up, 
  

   though 
  there 
  is 
  certainly 
  much 
  igneous 
  material 
  therein. 
  Mr. 
  Teall 
  

   had 
  spoken 
  of 
  the 
  association 
  of 
  granite 
  and 
  diorite 
  in 
  two 
  ways, 
  as 
  

   if 
  the 
  rocks 
  occurring 
  in 
  the 
  one 
  case 
  massive, 
  in 
  the 
  other 
  foliated, 
  

   were 
  of 
  the 
  same 
  age 
  ; 
  he 
  was 
  not 
  certain 
  about 
  this 
  identity. 
  

   He 
  still 
  thought 
  that 
  in 
  the 
  granulitic 
  series 
  there 
  were 
  rocks 
  very 
  

   difficult 
  to 
  explain, 
  on 
  the 
  view 
  that 
  they 
  are 
  merely 
  crushed- 
  

   out 
  igneous 
  rocks, 
  though 
  what 
  their 
  origin 
  was 
  he 
  was 
  unprepared 
  

   to 
  say. 
  He 
  knew 
  them 
  in 
  other 
  parts 
  of 
  the 
  world, 
  and 
  was 
  not 
  

   satisfied 
  with 
  the 
  dynamic-deformation 
  explanation. 
  We 
  have 
  to 
  

   explain 
  a 
  process 
  curiously 
  imitative 
  of 
  sedimentation. 
  He 
  did 
  

   not 
  think 
  Mr. 
  Teall's 
  experiments 
  quite 
  reproduced 
  the 
  conditions 
  

   occurring 
  in 
  nature. 
  In 
  regard 
  to 
  both 
  the 
  granulitic 
  and 
  thehorn- 
  

   blendic 
  series 
  his 
  difficulty 
  was 
  to 
  account 
  not 
  for 
  the 
  fine, 
  but 
  for 
  the 
  

   broad 
  banding 
  on 
  the 
  mechanical 
  deformation 
  theory. 
  He 
  exhibited 
  

  

  