﻿Vol. 
  53-1 
  EOCKS 
  AND 
  FOSSTLS 
  KROM 
  FRANZ 
  JOSEF 
  LAND. 
  485 
  

  

  constituents 
  is 
  clearly 
  shown. 
  The 
  amount 
  of 
  interstitial 
  matter 
  

   varies 
  considerably 
  in 
  different 
  specimens. 
  It 
  is 
  very 
  small 
  in 
  

   amount 
  in 
  the 
  massive 
  varieties, 
  but 
  in 
  some 
  of 
  the 
  vesicular 
  forms 
  

   it 
  becomes 
  an 
  important 
  constituent. 
  

  

  The 
  most 
  interesting 
  type 
  of 
  interstitial 
  matter 
  is 
  the 
  palagonitic. 
  

   Palagonite 
  is 
  especially 
  abundant 
  in 
  the 
  amygdaloidal 
  varieties, 
  

   where 
  it 
  occurs 
  not 
  only 
  wedged 
  in 
  between 
  the 
  crystalline 
  

   constituents, 
  but 
  also 
  as 
  the 
  infilling 
  material 
  of 
  some 
  of 
  the 
  

   amygdaloids. 
  It 
  is 
  a 
  soft 
  black 
  or 
  greenish-black 
  substance, 
  

   -which 
  can 
  be 
  readily 
  scratched 
  with 
  the 
  finger-nail 
  and 
  cut 
  with 
  

   a 
  knife. 
  The 
  powder 
  has 
  a 
  soft 
  unctuous 
  feel 
  when 
  rubbed 
  

   between 
  the 
  fingers. 
  Heated 
  in 
  a 
  closed 
  tube 
  it 
  gives 
  off 
  a 
  large 
  

   amount 
  of 
  water. 
  It 
  is 
  readily 
  acted 
  upon 
  by 
  hydrochloric 
  acid, 
  

   and 
  fragments 
  leave 
  behind 
  a 
  white 
  siliceous 
  pseudomoroh. 
  Under 
  

   the 
  microscope, 
  in 
  very 
  thin 
  sections, 
  it 
  is 
  usually 
  seen 
  to 
  be 
  of 
  

   a 
  deep 
  brown 
  colour; 
  but 
  occasionally 
  it 
  contains 
  green 
  zones 
  

   arranged 
  parallel 
  with 
  the 
  boundaries 
  of 
  the 
  space 
  which 
  it 
  

   occupies. 
  In 
  its 
  general 
  appearance, 
  and 
  in 
  the 
  presence 
  of 
  this 
  

   zonal 
  structure, 
  it 
  resembles 
  the 
  palagonite 
  from 
  deep-sea 
  deposits 
  

   described 
  by 
  Messrs. 
  Murray 
  & 
  Kenard. 
  1 
  When 
  viewed 
  with 
  

   crossed 
  nicols 
  the 
  palagonite 
  is 
  seen 
  to 
  be 
  doubly-refracting. 
  It 
  

   appears 
  to 
  be 
  formed 
  of 
  minute 
  interlacing 
  fibres 
  or 
  scales 
  of 
  a 
  

   brown 
  or, 
  more 
  rarely, 
  of 
  a 
  green 
  colour. 
  The 
  double 
  refraction 
  

   of 
  the 
  deep-brown 
  palagonite 
  enables 
  us 
  at 
  once 
  to 
  distinguish 
  it 
  

   from 
  the 
  isotropic 
  paler 
  brown 
  glass 
  with 
  which 
  it 
  is 
  sometimes 
  

   associated, 
  and 
  out 
  of 
  which 
  it 
  has 
  been 
  formed 
  by 
  hydration. 
  

   The 
  following 
  analysis 
  of 
  this 
  substance 
  was 
  made. 
  Analyses 
  of 
  

   palagonite 
  and 
  of 
  the 
  closely-related 
  'hullite' 
  are 
  quoted 
  for 
  com- 
  

   narison 
  : 
  — 
  

  

  I. 
  II. 
  III. 
  IV. 
  V. 
  

  

  SiO, 
  35-48 
  4126 
  4473 
  4(V76 
  3944 
  

  

  Al„6 
  3 
  8-30 
  8-60 
  1626 
  17-71 
  1035 
  

  

  Fe,0 
  3 
  12-30 
  25-32 
  1457 
  1-73 
  2072 
  

  

  Fe'O 
  14-60 
  ... 
  ... 
  10-92 
  3-70 
  

  

  MnO 
  ... 
  289 
  0-44 
  trace 
  

  

  CaO 
  104 
  5-59 
  188 
  1156 
  4'48 
  

  

  MgO 
  710 
  4-84 
  223 
  1037 
  7'47 
  

  

  Na.,0 
  3 
  92 
  106 
  450 
  183 
  

  

  K 
  2 
  trace 
  51 
  402 
  017 
  

  

  H 
  2 
  or 
  loss 
  on 
  ignition 
  ... 
  16 
  80 
  1279 
  9*56 
  ... 
  13*62 
  

  

  99-5 
  4 
  100-00 
  10064 
  10149 
  9978 
  

  

  I. 
  From 
  amygdules 
  in 
  basalt 
  at 
  Cape 
  Flora, 
  Franz 
  Josef 
  Land 
  (Teall). 
  

   11. 
  Palagonite 
  from 
  Patagonia, 
  Sicily. 
  The 
  insoluble 
  residue 
  ( 
  10 
  99 
  %) 
  is 
  

   deducted 
  and 
  the 
  remainder 
  calculated 
  to 
  100. 
  Quoted 
  from 
  Zirkel, 
  

   'Lehrbuch 
  der 
  Petrographie,' 
  2nd 
  ed. 
  vol. 
  iii. 
  (1894) 
  p. 
  689. 
  

   III. 
  Palagonite 
  from 
  South 
  Pacific. 
  Analysis 
  by 
  Sipocz, 
  Challenger 
  ' 
  Beport 
  

  

  on 
  Deep-Sea 
  Deposits,' 
  p. 
  307. 
  

   IV. 
  Basic 
  glass 
  from 
  the 
  centre 
  of 
  the 
  mass 
  from 
  which 
  the 
  palagonite 
  (III) 
  was 
  

   obtained. 
  

   V. 
  'Hullite' 
  from 
  Carnmoney 
  Hill, 
  near 
  Belfast. 
  Analysis 
  by 
  Hard 
  man. 
  

   Quoted 
  from 
  Sollas 
  & 
  Mc 
  Henry, 
  'On 
  a 
  Volcanic 
  Neck 
  of 
  Tertiary 
  

   Age 
  in 
  Co. 
  Galway,' 
  Trans. 
  Boy. 
  'Irish 
  Acad. 
  vol. 
  xxx. 
  (1896) 
  p. 
  734. 
  

  

  1 
  ' 
  Report 
  on 
  Deep-Sea 
  Deposits,' 
  Chall. 
  Exp 
  , 
  p 
  304. 
  

  

  