﻿Vol. 
  53.] 
  EOCKS 
  AND 
  FOSSILS 
  FEOM 
  FBANZ 
  JOSEF 
  LAND. 
  511 
  

  

  The 
  subangular 
  pebbles 
  are 
  formed 
  of 
  basalt, 
  sandstone, 
  and 
  black 
  

   radiolarian 
  chert. 
  A 
  section 
  of 
  the 
  chert 
  has 
  been 
  examined 
  by 
  

   Dr. 
  G. 
  J. 
  Hinde, 
  F.R.S., 
  who 
  has 
  kindly 
  furnished 
  us 
  with 
  the 
  

   following 
  description 
  : 
  — 
  

  

  ' 
  The 
  thin 
  section 
  of 
  the 
  small 
  rolled 
  pebble 
  of 
  light- 
  

   coloured 
  chert 
  from 
  Franz 
  Josef 
  Land 
  is 
  seen 
  under 
  the 
  microscope 
  

   to 
  be 
  filled 
  with 
  casts 
  of 
  radiolaria. 
  The 
  structure 
  of 
  these 
  

   organisms, 
  as 
  is 
  usually 
  the 
  case, 
  is 
  now 
  entirely 
  obliterated, 
  and 
  

   they 
  appear 
  as 
  minute 
  transparent 
  bodies 
  with 
  circular, 
  oval, 
  or 
  

   discoidal 
  outlines 
  in 
  the 
  cherty 
  matrix. 
  Most 
  of 
  them 
  are 
  smooth, 
  

   but 
  a 
  few 
  have 
  projecting 
  spines. 
  They 
  range 
  from 
  0*06 
  to 
  

   0-19 
  mm. 
  in 
  diameter 
  ; 
  in 
  general, 
  the 
  forms 
  are 
  relatively 
  smaller 
  

   than 
  those 
  usually 
  met 
  with 
  in 
  chert. 
  Judging 
  from 
  their 
  out- 
  

   lines, 
  several 
  genera 
  are 
  represented 
  in 
  the 
  section 
  ; 
  the 
  most 
  

   numerous 
  are 
  the 
  simple 
  round 
  and 
  oval 
  forms 
  belonging 
  to 
  Ceno- 
  

   sphcera 
  and 
  Cenellipsis, 
  and 
  the 
  rarer 
  spined 
  ones 
  may 
  be 
  probably 
  

   referred 
  to 
  Xiphostylus 
  and 
  Dorysplicera. 
  Though 
  the 
  horizon 
  of 
  

   the 
  rock 
  from 
  which 
  this 
  pebble 
  comes 
  cannot 
  be 
  positively 
  

   determined 
  from 
  these 
  imperfectly 
  preserved 
  radiolaria, 
  it 
  is 
  not 
  

   improbably 
  of 
  Palaeozoic 
  age. 
  The 
  character 
  of 
  the 
  chert 
  itself 
  

   is 
  precisely 
  similar 
  to 
  that 
  of 
  the 
  radiolarian 
  chert 
  of 
  the 
  

   Palasozoic 
  rocks 
  of 
  Devon, 
  Cornwall, 
  and 
  the 
  South 
  of 
  Scotland.' 
  

  

  It 
  is 
  a 
  curious 
  circumstance 
  that 
  among 
  the 
  few 
  specimens 
  

   brought 
  from 
  Joinville 
  Island 
  in 
  the 
  Antarctic 
  region, 
  south 
  of 
  

   the 
  Falkland 
  Isles, 
  was 
  one 
  of 
  radiolarian 
  chert 
  ; 
  thus 
  this 
  rock 
  

   has 
  been 
  found, 
  though 
  not 
  in 
  situ, 
  in 
  the 
  most 
  northerly 
  and 
  most 
  

   southerly 
  lands 
  yet 
  visited. 
  

  

  Rocks 
  showing 
  cone-in-cone 
  structure 
  are 
  very 
  abundant 
  near 
  

   Cape 
  Flora, 
  and 
  have 
  been 
  found 
  at 
  several 
  localities. 
  Numerous 
  

   specimens 
  have 
  been 
  collected, 
  but 
  unfortunately 
  not 
  one 
  of 
  them 
  

   was 
  found 
  in 
  place, 
  so 
  that 
  the 
  exact 
  horizon 
  from 
  which 
  they 
  come 
  

   cannot 
  be 
  determined. 
  As 
  they 
  are 
  found 
  all 
  round 
  the 
  Cape, 
  and 
  

   sometimes 
  high 
  up 
  on 
  the 
  talus, 
  it 
  is 
  probable 
  that 
  they 
  form 
  a 
  

   band 
  or 
  bands 
  situated 
  not 
  far 
  below 
  the 
  basalt. 
  ' 
  

  

  The 
  rock 
  is 
  an 
  argillaceous 
  limestone, 
  and 
  the 
  carbonate, 
  which 
  

   has 
  produced 
  the 
  structure 
  by 
  its 
  attempts 
  to 
  crystallize 
  under 
  

   unfavourable 
  circumstances, 
  is 
  rich 
  in 
  lime 
  and 
  poor 
  in 
  iron 
  and 
  

   magnesia. 
  1 
  

  

  VI. 
  The 
  Relations 
  of 
  the 
  vaeiotjs 
  Fossilifeeotjs 
  Hoeizons. 
  

  

  In 
  order 
  to 
  give 
  some 
  idea 
  of 
  the 
  relations 
  of 
  the 
  various 
  beds 
  

   of 
  fossils 
  above 
  noticed, 
  and 
  of 
  their 
  probable 
  place 
  in 
  the 
  geological 
  

   sequence, 
  a 
  vertical 
  section 
  (fig. 
  4) 
  has 
  been 
  made 
  of 
  the 
  strata 
  at 
  

   Cape 
  Flora, 
  relying 
  upon 
  the 
  various 
  heights 
  above 
  the 
  sea, 
  at 
  

   which 
  the 
  different 
  beds 
  are 
  said 
  to 
  occur, 
  for 
  the 
  position 
  of 
  these 
  

  

  1 
  See 
  G. 
  A. 
  J. 
  Cole, 
  ' 
  On 
  some 
  Examples 
  of 
  Cone-in-cone 
  Structure,' 
  Mm. 
  

   Mag. 
  vol. 
  x. 
  (1892) 
  p. 
  136. 
  

  

  