﻿88 
  

  

  PROF. 
  T. 
  &. 
  BONXEY 
  OX 
  TWO 
  TEAYEBSES 
  OF 
  THE 
  

  

  occasional 
  greener 
  bands. 
  This, 
  in 
  about 
  4 
  yards, 
  passes 
  back 
  into 
  

   the 
  green 
  schist, 
  which 
  is, 
  perhaps, 
  at 
  first 
  a 
  shade 
  more 
  micaceous 
  

   than 
  usual, 
  but 
  soon 
  becomes 
  perfectly 
  normal 
  chloritic 
  schist 
  *. 
  

  

  From 
  this 
  description 
  it 
  will, 
  I 
  hope, 
  be 
  understood 
  that 
  the 
  

   calc-mica-schists 
  and 
  the 
  chloritic 
  schists 
  are 
  associated 
  in 
  the 
  same 
  

  

  Fig. 
  6. 
  — 
  Bough 
  Sketch 
  of 
  folded 
  OaJc-mica-schist 
  above 
  

   Windiscli-Matrei. 
  

  

  a. 
  Band 
  about 
  l%" 
  thick, 
  chiefly 
  dark 
  mica. 
  

  

  b. 
  Light-coloured 
  calc-inica-rock 
  with 
  brownish 
  spots. 
  

  

  c. 
  Idem, 
  darker 
  in 
  colour. 
  

  

  d. 
  Idem, 
  more 
  distinctly 
  banded. 
  

  

  e. 
  f, 
  g. 
  Like 
  k, 
  but 
  more 
  brown-spotted. 
  

   h. 
  Browner, 
  more 
  micaceous 
  band. 
  

  

  The 
  dark 
  divisional 
  lines 
  are 
  the 
  distinct 
  bands 
  of 
  dark 
  mica, 
  at 
  most 
  £" 
  thick. 
  

   The 
  vertical 
  lines 
  indicate 
  the 
  imperfectly 
  developed 
  cleavage-foliation. 
  

  

  manner 
  as 
  ordinary 
  stratified 
  rocks, 
  and 
  that 
  there 
  is 
  a 
  real, 
  

   though 
  fairly 
  rapid, 
  passage 
  from 
  the 
  one 
  to 
  the 
  other, 
  so 
  that 
  it 
  

   seems 
  impossible 
  to 
  regard 
  the 
  chloritic 
  rock 
  as 
  the 
  modification 
  

   of 
  a 
  basic 
  igneous 
  rock, 
  either 
  intrusive 
  or 
  interbedded. 
  

  

  Presently 
  another 
  change 
  is 
  shown 
  in 
  the 
  face 
  of 
  the 
  crags 
  : 
  for 
  the 
  

   rock 
  has 
  become 
  a 
  highly 
  calcareous 
  mica-schist, 
  almost 
  a 
  marble. 
  

   It 
  exhibits 
  every 
  indication 
  which 
  we 
  should 
  expect 
  from 
  a 
  rock 
  

   originally 
  stratified, 
  the 
  stratification-foliation 
  dipping 
  at 
  about 
  70° 
  

   slightly 
  to 
  W. 
  of 
  S. 
  It 
  is 
  exposed 
  for 
  about 
  25 
  paces 
  by 
  the 
  path 
  ; 
  

   but, 
  as 
  this 
  crosses 
  the 
  strike 
  obliquely, 
  perhaps 
  making 
  an 
  angle 
  of 
  

   30°, 
  the 
  thickness 
  cannot 
  be 
  more 
  than 
  35 
  feet. 
  To 
  this, 
  after 
  a 
  

   few 
  yards 
  covered 
  with 
  debris, 
  succeeds 
  a 
  very 
  micaceous 
  variety 
  of 
  

   * 
  For 
  the 
  microscopic 
  structure 
  of 
  these 
  rocks, 
  see 
  Appendix, 
  pp. 
  107-109. 
  

  

  