﻿158 
  T. 
  F. 
  JAMIES0N 
  ON 
  THE 
  CRAG-SHELL 
  

  

  rough 
  pebbly 
  gravel, 
  composed 
  of 
  gravel, 
  sand, 
  and 
  stones, 
  all 
  water- 
  

   washed 
  and 
  partly 
  water-worn. 
  The 
  stones 
  are 
  of 
  all 
  sizes 
  up 
  to 
  a 
  

   foot 
  or 
  a 
  foot 
  and 
  a 
  half 
  in 
  length. 
  They 
  consist 
  of 
  many 
  kinds 
  of 
  

   rocks. 
  Gneiss 
  and 
  spotted 
  mica-schist 
  predominate 
  ; 
  but 
  there 
  are 
  a 
  

   great 
  many 
  pieces 
  of 
  yellow 
  limestone, 
  grey 
  limestone 
  and 
  shaly 
  lime- 
  

   stone. 
  Several 
  fragments 
  of 
  purplish 
  red 
  sandstone, 
  some 
  of 
  granite, 
  

   one 
  or 
  two 
  of 
  serpentine, 
  and 
  a 
  flint 
  may 
  be 
  also 
  found. 
  In 
  form 
  

   the 
  stones 
  are 
  for 
  the 
  most 
  part 
  subangular 
  ; 
  but 
  some 
  well-rounded 
  

   pebbles 
  also 
  occur. 
  Small 
  crumbs 
  of 
  shells 
  are 
  disseminated 
  all 
  

   through 
  this 
  pebbly 
  gravel; 
  and 
  in 
  it 
  I 
  got 
  a 
  small 
  specimen 
  of 
  

   the 
  Crag 
  shell 
  Fusus 
  contrarius, 
  var. 
  carinata, 
  much 
  worn. 
  This 
  

   mass 
  of 
  rough 
  pebbly 
  gravel 
  does 
  not 
  seem 
  to 
  extend 
  continuously 
  

   along 
  the 
  bank 
  with 
  the 
  same 
  thickness 
  for 
  any 
  great 
  distance. 
  In 
  

   general 
  appearance 
  and 
  composition 
  it 
  seems 
  identical 
  with 
  the 
  gravel 
  

   of 
  the 
  Kippet 
  Hills. 
  

  

  Above 
  it 
  there 
  is 
  a 
  thickness 
  of 
  22 
  feet 
  made 
  up 
  of 
  fine 
  brownish 
  

   grey 
  sand 
  with 
  seams 
  of 
  coarse 
  gravel 
  and 
  reddish 
  silty 
  sand 
  alter- 
  

   nating 
  with 
  one 
  another. 
  Crumbs 
  of 
  shells 
  and 
  small 
  limestone 
  

   debris 
  occur 
  in 
  the 
  seams 
  of 
  coarse 
  gravel 
  all 
  the 
  way 
  to 
  the 
  top, 
  

   where 
  it 
  meets 
  the 
  over-lying 
  clay, 
  the 
  junction 
  with 
  which 
  forms 
  

   an 
  irregularly 
  undulating 
  line, 
  as 
  if 
  the 
  sandy 
  beds 
  had 
  suffered 
  

   some 
  denudation. 
  

  

  ': 
  The 
  bed 
  of 
  clay 
  forming 
  the 
  top 
  of 
  the 
  bank 
  at 
  this 
  spot 
  seems 
  to 
  

   be 
  a 
  mixture 
  of 
  red 
  clay 
  with 
  some 
  patches 
  of 
  a 
  coarse 
  grey 
  clay 
  

   intermingled 
  ; 
  but 
  it 
  is 
  not 
  very 
  fully 
  exposed. 
  There 
  are 
  several 
  

   stones 
  in 
  it, 
  of 
  all 
  sizes, 
  up 
  to 
  2| 
  feet 
  in 
  length, 
  and 
  of 
  various 
  kinds, 
  

   viz. 
  gneiss, 
  mica-schist, 
  granite, 
  and 
  greenstone. 
  This 
  clay 
  shows 
  

   no 
  distinct 
  stratification, 
  and 
  is 
  of 
  coarse 
  quality 
  and 
  not 
  laminated. 
  

  

  2. 
  Section 
  at 
  Clochtow. 
  

  

  feet. 
  

  

  Schistose 
  rock 
  30 
  

  

  Grey 
  rubbish 
  11 
  

  

  Fine 
  sand 
  and 
  silt 
  56 
  

  

  Coarse 
  clay 
  24 
  

  

  Total 
  121 
  

  

  In 
  this 
  section 
  the 
  coarse 
  grey 
  rubbish 
  next 
  the 
  rock 
  resembles 
  

   that 
  in 
  the 
  section 
  already 
  described, 
  consisting 
  of 
  small 
  rock-debris 
  

   packed 
  in 
  a 
  little 
  muddy 
  matter 
  of 
  the 
  same 
  mineral 
  nature. 
  Here 
  

   the 
  rough 
  pebbly 
  gravel 
  is 
  wanting, 
  and 
  the 
  thick 
  mass 
  of 
  sand 
  and 
  

   sandy 
  silt 
  seems 
  to 
  contain 
  scarcely 
  any 
  stones 
  or 
  pebbles 
  of 
  any 
  kind. 
  

  

  There 
  is 
  even 
  an 
  absence 
  of 
  small 
  gravel, 
  the 
  whole 
  mass 
  being 
  

   fine-grained, 
  and 
  consisting 
  of 
  brownish-grey 
  sand 
  interstratified 
  

   with 
  beds 
  of 
  reddish 
  clayey 
  silt 
  and 
  reddish 
  sand, 
  which 
  appear 
  to 
  

   occur 
  in 
  all 
  parts 
  of 
  the 
  mass 
  ; 
  but 
  the 
  red 
  tinge 
  seems 
  to 
  prevail 
  

   more 
  towards 
  the 
  top. 
  The 
  meeting 
  of 
  this 
  thick 
  mass 
  of 
  sand 
  and 
  

   silt 
  with 
  the 
  coarse 
  grey 
  rubbish 
  beneath 
  appears 
  to 
  be 
  sharp 
  and 
  

   sudden 
  ; 
  there 
  is 
  no 
  graduating 
  into 
  each 
  other, 
  so 
  far 
  as 
  I 
  could 
  see. 
  

   At 
  the 
  top, 
  where 
  it 
  meets 
  the 
  overlying 
  clay, 
  the 
  line 
  of 
  junction 
  

   seems 
  to 
  be 
  undulating. 
  This 
  clay 
  above 
  it 
  is 
  not 
  very 
  extensively 
  

  

  