﻿CKYSTALLINE 
  KOCKS 
  OP 
  THE 
  ALPS. 
  109 
  

  

  No. 
  I. 
  No. 
  II. 
  No. 
  III. 
  

  

  SiO 
  43-48 
  50-80 
  47-44 
  

  

  Al 
  14-54 
  23-08 
  15-26 
  

  

  Fe0 
  3 
  10-20 
  6-44 
  4-42 
  

  

  FeO 
  7-87 
  4-09 
  8-36 
  

  

  CaO 
  , 
  . 
  . 
  . 
  6-29 
  4-75 
  5-^9 
  

  

  MgO 
  11-11 
  1-70 
  12-15 
  

  

  KO+%0.. 
  2-68 
  4-50 
  4-58 
  

  

  H 
  2 
  2-51 
  3-55 
  2-27 
  

  

  C0 
  2 
  -97 
  -62 
  -75 
  

  

  99-65 
  99-53 
  100-52 
  

  

  No. 
  I. 
  (/3) 
  of 
  above 
  description. 
  No. 
  II. 
  (y) 
  the 
  same. 
  

   No. 
  III. 
  (g) 
  the 
  same. 
  

  

  Nos. 
  I. 
  and 
  III. 
  indicate 
  that 
  the 
  composition 
  of 
  the 
  rock 
  is 
  not 
  

   very 
  different 
  from 
  that 
  of 
  a 
  basalt, 
  and 
  suggest 
  the 
  possibility 
  that 
  

   the 
  original 
  material 
  might 
  be 
  a 
  basic 
  tuff. 
  The 
  analysis 
  of 
  No. 
  II. 
  

   is 
  nearer 
  that 
  of 
  some 
  ordinary 
  argillaceous 
  rocks, 
  and 
  may 
  indicate 
  

   that 
  the 
  original 
  material 
  was 
  a 
  clay 
  with 
  perhaps 
  a 
  slight 
  admix- 
  

   ture 
  of 
  basic 
  ash. 
  A 
  detailed 
  study 
  of 
  No. 
  I. 
  seems 
  to 
  indicate 
  the 
  

   probability 
  of 
  a 
  fair 
  amount 
  either 
  of 
  free 
  quartz 
  or 
  of 
  a 
  silicate 
  with 
  

   a 
  higher 
  percentage 
  of 
  ISi0 
  2 
  than 
  kyanite 
  being 
  also 
  present, 
  if 
  the 
  

   identification 
  of 
  the 
  last 
  mineral 
  be 
  correct. 
  

  

  Discussion-. 
  

  

  The 
  Pkesident 
  said 
  that 
  the 
  paper 
  was 
  a 
  valuable 
  addition 
  to 
  

   studies 
  which 
  the 
  Author 
  had 
  made 
  especially 
  his 
  own. 
  By 
  adopt- 
  

   ing 
  three 
  instead 
  of 
  four 
  groups 
  he 
  had 
  simplified 
  the 
  classification. 
  

   It 
  was 
  clear 
  that 
  in 
  the 
  Alps, 
  as 
  elsewhere, 
  there 
  was 
  at 
  the 
  base 
  

   of 
  the 
  Archaean 
  a 
  series 
  of 
  highly 
  gneissic 
  rocks, 
  whilst 
  in 
  an 
  upper 
  

   division 
  were 
  indications 
  which 
  could 
  only 
  be 
  reconciled 
  with 
  the 
  

   idea 
  of 
  aqueous 
  deposition. 
  It 
  was 
  noteworthy 
  that 
  the 
  Author 
  

   had 
  not 
  countenanced 
  any 
  hypothetical 
  parallels 
  with 
  Archsean 
  rocks 
  

   on 
  the 
  other 
  side 
  of 
  the 
  Atlantic. 
  

  

  Mr. 
  Teall 
  commented 
  on 
  the 
  great 
  divergence 
  of 
  opinion 
  between 
  

   the 
  Author 
  and 
  geologists 
  like 
  Heim. 
  The 
  former, 
  he 
  considered, 
  

   held 
  exceptional 
  views, 
  though 
  there 
  was 
  evidence 
  in 
  his 
  papers 
  of 
  

   increasing 
  faith 
  in 
  dynamic 
  metamorphism. 
  The 
  Author 
  claims 
  to 
  

   be 
  able 
  to 
  distinguish 
  between 
  Archsean 
  schists 
  and 
  later 
  rocks 
  ; 
  

   the 
  opposite 
  school 
  asserts 
  that 
  rocks 
  of 
  later 
  date 
  have 
  been 
  re- 
  

   duced 
  to 
  the 
  condition 
  of 
  crystalline 
  schists. 
  

  

  As 
  a 
  test 
  case, 
  he 
  would 
  mention 
  the 
  discovery 
  of 
  Belemnites 
  

   by 
  Charpentier 
  and 
  Studer 
  in 
  the 
  garnetiferous 
  mica-schists 
  of 
  the 
  

   Nufener 
  Pass 
  and 
  Fontana. 
  Dr. 
  Griibenmann 
  of 
  Frauenfeld 
  had 
  

   recently 
  given 
  an 
  elaborate 
  petrographical 
  description 
  of 
  these 
  rocks. 
  

  

  As 
  regards 
  the 
  lower 
  division, 
  it 
  was 
  held 
  that 
  primary 
  foliation 
  

  

  