﻿18 
  

  

  PEOE. 
  T. 
  G. 
  BONNET 
  ON 
  THE 
  SECTIONS 
  NEAE 
  [Feb. 
  1 
  897,. 
  

  

  At 
  the 
  time 
  of 
  my 
  last 
  visit 
  the 
  junction 
  of 
  the 
  main 
  mass 
  of 
  

   marble 
  with 
  the 
  overlying 
  Jurassic 
  rock 
  could 
  be 
  seen 
  at 
  three 
  

   places. 
  One 
  is 
  in 
  a 
  very 
  small 
  opening 
  on 
  the 
  western 
  side 
  of 
  the 
  

   pass, 
  just 
  beyond 
  the 
  end 
  of 
  the 
  crag 
  of 
  marble 
  overhanging 
  the 
  road. 
  

   Here 
  we 
  found 
  in 
  descending 
  order 
  (fig. 
  2) 
  a 
  subcrystalline 
  lime- 
  

   stone 
  weathering 
  bluish 
  - 
  

  

  grey, 
  banded 
  with 
  a 
  blackish 
  Fjo>. 
  2. 
  

  

  slaty 
  rock, 
  about 
  18 
  inches 
  ; 
  

   4 
  black 
  messy 
  stuff 
  ' 
  (the 
  

   above 
  slaty 
  rock 
  crushed), 
  

   about 
  6 
  inches 
  ; 
  the 
  slabby 
  

   marble 
  (crushed). 
  The 
  two 
  

   other 
  sections 
  are 
  on 
  the 
  

   eastern 
  side 
  of 
  the 
  pass, 
  and 
  

   were 
  exposed 
  in 
  small 
  quar- 
  

   ries 
  which 
  had 
  been 
  opened 
  

   by 
  the 
  roadside 
  since 
  my 
  

   visit 
  in 
  1894. 
  The 
  first 
  was 
  

   about 
  120 
  yards 
  from 
  the 
  

   • 
  dependance.' 
  Here 
  we 
  see 
  

   (1) 
  a 
  slabby, 
  dull-coloured, 
  

   subcrystalline 
  limestone, 
  

   parted 
  by 
  darker 
  and 
  more 
  

   argillaceous 
  bands 
  ; 
  (2) 
  a 
  

   foot 
  or 
  so 
  of 
  'dark 
  messy 
  

   stuff 
  ' 
  corresponding 
  with 
  

   that 
  in 
  the 
  last 
  section 
  ; 
  

   (3) 
  the 
  marble, 
  1 
  which 
  rose 
  

   to 
  a 
  height 
  of 
  about 
  15 
  feet 
  

  

  above 
  the 
  road. 
  Its 
  surface 
  has 
  a 
  somewhat 
  wavy 
  outline, 
  and 
  its 
  

   upper 
  part 
  is 
  evidently 
  in 
  a 
  rather 
  crushed 
  condition. 
  This 
  is 
  the 
  

   top 
  of 
  the 
  mass 
  of 
  marble, 
  which 
  in 
  1891 
  we 
  traced 
  up 
  the 
  slope 
  of 
  

   the 
  valley 
  below, 
  and 
  which 
  passes 
  behind 
  the 
  ' 
  dependance,' 
  forming 
  

   the 
  crag 
  by 
  the 
  roadside 
  farther 
  west. 
  Two 
  other 
  small 
  pits, 
  near 
  

   together, 
  are 
  found 
  about 
  40 
  yards 
  east 
  of 
  that 
  just 
  described, 
  each 
  

   showing 
  a 
  similar 
  section. 
  In 
  all 
  these 
  exposures 
  two 
  rocks 
  of 
  very 
  

   different 
  mineral 
  character 
  appear 
  in 
  close 
  sequence, 
  and 
  suggest 
  

   by 
  their 
  aspect 
  some 
  amount 
  of 
  faulting. 
  

  

  1 
  = 
  Marble, 
  rather 
  crushed. 
  

  

  X 
  =Top 
  slab 
  : 
  specimen 
  taken. 
  

  

  2 
  = 
  Subcrystalline 
  limestone 
  with 
  argil- 
  

  

  laceous 
  slaty 
  partings. 
  

   2'= 
  Crushed 
  slaty 
  or 
  shaly 
  rock 
  ('black 
  

   messy 
  stuff'), 
  about 
  6 
  inches 
  thick 
  at 
  

   most. 
  

  

  3 
  = 
  Debris. 
  

  

  On 
  previous 
  visits 
  I 
  had 
  observed 
  certain 
  macroscopic 
  differences 
  

   between 
  the 
  marble 
  and 
  the 
  admittedly 
  Jurassic 
  limestone, 
  but 
  on 
  

   this 
  occasion 
  became 
  more 
  than 
  ever 
  convinced 
  of 
  their 
  existence. 
  

   The 
  most 
  important 
  may 
  be 
  stated 
  as 
  follows 
  : 
  — 
  The 
  marble, 
  if 
  

   unstained, 
  is 
  lighter 
  in 
  colour 
  on 
  a 
  freshly 
  -broken 
  surface; 
  on 
  

   weathered 
  surfaces 
  it 
  turns 
  to 
  a 
  pale 
  fawn 
  colour, 
  with 
  occasional 
  

   browner 
  bands. 
  These 
  are 
  more 
  micaceous 
  and 
  project 
  a 
  little 
  

   from 
  the 
  rest 
  of 
  the 
  rock. 
  The 
  Jurassic 
  limestone 
  is 
  darker 
  

   in 
  colour, 
  becomes 
  greyish-blue 
  or 
  bluish-grey 
  in 
  weathering, 
  and 
  

  

  No. 
  2 
  of 
  the 
  section 
  described 
  on 
  p. 
  294 
  (op. 
  cit.). 
  

  

  