﻿306 
  LT.-GEN. 
  C. 
  A. 
  MCMAHON 
  & 
  CAPT. 
  A. 
  H. 
  MCMAHON 
  [Aug. 
  1 
  89 
  7, 
  

  

  Koh-i-Malik 
  Siah. 
  

  

  (1) 
  Eed 
  jasper 
  interspersed 
  with 
  white 
  quartz 
  and 
  chalcedony. 
  

  

  (2) 
  Epidote-rock, 
  composed 
  of 
  epidote- 
  and 
  quartz-crystals, 
  the 
  

  

  former 
  predominating. 
  The 
  quartz 
  contains 
  inclusions 
  of 
  

   ferric 
  oxide. 
  

  

  (3) 
  Chrysocolla, 
  in 
  a 
  matrix 
  composed 
  principally 
  of 
  silica, 
  with 
  

  

  fragments 
  of 
  mica 
  and 
  other 
  minerals. 
  

  

  (4) 
  Galena 
  or 
  sulphide 
  of 
  lead. 
  

  

  (5) 
  Small 
  fragments 
  of 
  basic 
  igneous 
  rocks. 
  

  

  (6) 
  Fragments 
  of 
  fine-grained 
  biotite-granite. 
  

  

  Malik 
  Dokhand. 
  

   Crystalline 
  granular 
  gypsum 
  (alabaster). 
  

  

  Malik 
  Ainak. 
  

  

  Selenite, 
  

  

  EXPLANATION 
  OF 
  PLATES. 
  

   Plate 
  XVIII. 
  

  

  Sketch-map 
  of 
  the 
  Baluchistan-Afghan 
  frontier, 
  on 
  the 
  scale 
  of 
  z-^rx^n 
  or 
  

   47 
  '3 
  miles 
  =1 
  inch. 
  

  

  Plate 
  XIX. 
  

   a=biotite. 
  <? 
  cZe 
  = 
  quartz. 
  /= 
  anthophyllite. 
  k= 
  hornblende, 
  o^olivine. 
  

  

  Fig. 
  1. 
  General 
  view 
  of 
  augite-hornblende-andesite. 
  No. 
  1424. 
  

  

  2. 
  Section 
  of 
  the 
  anthophyllite 
  seen 
  in 
  fig. 
  1 
  (enlarged). 
  

  

  3. 
  Brown-red 
  anthophyllite 
  (with 
  contact-halo) 
  enclosed 
  in 
  an 
  aggregate 
  

  

  of 
  pyroxene-grains 
  and 
  prisms, 
  the 
  granular 
  complex 
  having 
  the 
  form 
  

   of 
  a 
  crystal. 
  See 
  p. 
  298. 
  

  

  4. 
  Contemporaneous 
  crystallization 
  of 
  plagioclase 
  and 
  brown-red 
  antho- 
  

  

  phyllite. 
  See 
  p. 
  298. 
  

  

  5. 
  Olivine, 
  with 
  deposit 
  of 
  brown-red 
  anthophyllite 
  round 
  its 
  margin 
  ; 
  

  

  enlarged 
  from 
  No. 
  1424 
  (fig. 
  1). 
  See 
  p. 
  299. 
  

  

  6. 
  General 
  view 
  of 
  augite-hornblende-andesite, 
  No. 
  1438, 
  showing 
  olivine. 
  

  

  See 
  p. 
  299. 
  

  

  Plate 
  XX. 
  

  

  Fig. 
  1. 
  Augite-hornblende-andesite. 
  Another 
  portion 
  of 
  No. 
  1438 
  (PI. 
  XIX, 
  

   fig. 
  6). 
  

  

  2. 
  Felspathic 
  lava. 
  No. 
  3416. 
  See 
  p. 
  300. 
  

  

  3. 
  Quartz-syenite. 
  Corrosion 
  of 
  hornblende 
  by 
  quartz. 
  Between 
  d 
  and 
  k 
  

  

  and 
  between 
  c 
  and 
  h 
  the 
  quartz 
  has 
  eaten 
  deeply 
  into 
  the 
  hornblende 
  

   all 
  round. 
  At 
  d 
  it 
  has 
  forced 
  its 
  way 
  into 
  cleavage-cracks 
  ; 
  while 
  at 
  b 
  

   the 
  process 
  has 
  proceeded 
  further, 
  and 
  a 
  piece 
  has 
  been 
  split 
  off 
  from 
  

   the 
  main 
  crystal 
  of 
  hornblende. 
  See 
  p. 
  304. 
  

  

  4. 
  Quartz-syenite. 
  Corrosion 
  of 
  biotite 
  by 
  quartz. 
  The 
  quartz 
  has 
  cut 
  

  

  deeply 
  into 
  the 
  biotite 
  all 
  round 
  its 
  margin. 
  Between 
  b 
  and 
  d 
  

   the 
  quartz 
  by 
  its 
  solvent 
  action 
  has 
  nearly 
  severed 
  the 
  biotite 
  into 
  

   two 
  portions. 
  This 
  can 
  be 
  seen 
  with 
  the 
  aid 
  of 
  a 
  pocket-lens. 
  

  

  5. 
  Hornblende-biotite-granite. 
  Corrosion 
  of 
  hornblende 
  and 
  biotite 
  by 
  

  

  quartz. 
  The 
  biotite 
  has 
  at 
  d 
  been 
  cut 
  in 
  half 
  and 
  corroded 
  all 
  

   round 
  by 
  the 
  quartz. 
  Seven 
  distinct 
  bays 
  of 
  corrosion 
  can 
  be 
  counted. 
  

  

  6. 
  Hornblende-biotite-granite. 
  Corrosion 
  of 
  hornblende 
  by 
  quartz. 
  Bays 
  

  

  of 
  corrosion 
  are 
  to 
  be 
  seen 
  all 
  round 
  the 
  hornblende. 
  See 
  p. 
  303. 
  

  

  