﻿GRAVEL 
  BEDS 
  OF 
  ABERDEENSHIRE. 
  157 
  

  

  Pieces 
  of 
  Cyprina 
  islandica 
  are 
  numerous, 
  the 
  strong 
  massy 
  

   hinge 
  of 
  this 
  shell 
  having 
  withstood 
  the 
  tear 
  and 
  wear 
  better 
  than 
  

   most 
  others 
  ; 
  a 
  few 
  of 
  them 
  are 
  filled 
  with 
  concrete. 
  

  

  I 
  have 
  a 
  good 
  many 
  hinge-pieces 
  of 
  what 
  I 
  believe 
  to 
  be 
  

   Cyprina 
  rustica 
  ; 
  but 
  I 
  must 
  candidly 
  mention 
  that 
  the 
  Messrs. 
  S. 
  Y. 
  

   Wood 
  expressed 
  themselves 
  doubtful 
  as 
  to 
  their 
  identification, 
  

   thinking 
  they 
  might 
  belong 
  either 
  to 
  this 
  species 
  or 
  to 
  C. 
  islandica. 
  

   I 
  feel 
  confident, 
  however, 
  that 
  they 
  are 
  not 
  the 
  latter, 
  as 
  it 
  is 
  a 
  shell 
  

   I 
  am 
  quite 
  familiar 
  with 
  in 
  all 
  states 
  of 
  preservation, 
  it 
  being 
  per- 
  

   haps 
  the 
  most 
  plentiful 
  of 
  all 
  our 
  glacial 
  Mollusca, 
  and 
  also 
  quite 
  

   common 
  on 
  the 
  Aberdeenshire 
  coast 
  at 
  the 
  present 
  day 
  ; 
  and 
  I 
  find 
  

   no 
  difficulty 
  in 
  distinguishing 
  its 
  hinge 
  from 
  these 
  specimens 
  of 
  

   C. 
  rustica. 
  

  

  In 
  regard 
  to 
  the 
  shell-fragments 
  as 
  a 
  whole, 
  the 
  question 
  natu- 
  

   rally 
  arises 
  whether 
  some 
  of 
  them 
  may 
  not 
  be 
  of 
  glacial 
  age, 
  con- 
  

   temporaneous 
  with 
  the 
  period 
  during 
  which 
  the 
  gravel 
  was 
  accumu- 
  

   lated. 
  So 
  far 
  as 
  I 
  can 
  judge 
  from 
  their 
  appearance 
  and 
  state 
  of 
  

   preservation, 
  I 
  incline 
  to 
  think 
  this 
  question 
  must 
  be 
  answered 
  in 
  

   the 
  negative, 
  and 
  that 
  the 
  shells 
  are 
  probably 
  all 
  derivatives 
  from 
  

   older 
  strata, 
  and 
  none 
  of 
  them 
  of 
  the 
  glacial 
  age 
  to 
  which 
  the 
  accu- 
  

   mulation 
  of 
  the 
  gravel 
  itself 
  must 
  be 
  assigned. 
  

  

  Details 
  of 
  a 
  few 
  Sections 
  on 
  the 
  Coast 
  of 
  Slains. 
  

  

  1. 
  Section 
  on 
  the 
  Coast 
  immediately 
  to 
  the 
  South 
  of 
  the 
  Old 
  Castle 
  

   of 
  Slains. 
  

  

  Commencing 
  at 
  the 
  bottom 
  at 
  high-water 
  mark 
  we 
  have 
  : 
  — 
  

  

  feet. 
  

  

  1. 
  Mica-schist 
  about 
  50 
  

  

  2. 
  Stratum 
  of 
  coarse 
  grey 
  rubbish 
  10 
  

  

  3. 
  Pebbly 
  gravel 
  16 
  

  

  4. 
  Fine 
  gravel, 
  sand, 
  and 
  silt 
  22 
  

  

  5. 
  Keddish 
  clay 
  11 
  

  

  Total 
  109 
  

  

  The 
  coarse 
  grey 
  rubbish 
  next 
  the 
  rock 
  is 
  here 
  made 
  up 
  almost 
  

   entirely 
  of 
  the 
  debris 
  of 
  spotted 
  mica-schist, 
  apparently 
  the 
  same 
  as 
  

   that 
  of 
  the 
  subjacent 
  rock 
  (andalusite 
  schist). 
  It 
  appears 
  to 
  contain 
  

   none 
  of 
  the 
  limestone 
  debris 
  or 
  broken 
  shells. 
  The 
  schistose 
  frag- 
  

   ments 
  in 
  it 
  are 
  angular, 
  and 
  show 
  no 
  marks 
  of 
  glaciation, 
  so 
  far 
  as 
  

   I 
  observed. 
  The 
  mass 
  appears 
  to 
  be 
  quite 
  unstratified 
  ; 
  and 
  the 
  in- 
  

   cluded 
  fragments 
  lie 
  in 
  all 
  positions 
  and 
  are 
  packed 
  in 
  small 
  debris 
  

   of 
  the 
  same 
  nature. 
  The 
  proportion 
  of 
  fine 
  impalpable 
  mud 
  is 
  small 
  

   compared 
  with 
  what 
  is 
  seen 
  in 
  a 
  typical 
  Boulder- 
  clay, 
  such 
  as 
  that 
  

   at 
  the 
  Bay 
  of 
  Nigg. 
  

  

  Lying 
  immediately 
  above 
  this 
  grey 
  rubbish 
  there 
  is 
  a 
  bed 
  of 
  coarse 
  

   gravel 
  and 
  sand 
  containing 
  shell- 
  crumbs 
  and 
  small 
  limestone 
  debris. 
  

   It 
  is 
  an 
  open 
  washed 
  gravel, 
  quite 
  unlike 
  the 
  stuff 
  beneath, 
  and 
  

   meets 
  the 
  latter 
  suddenly 
  without 
  graduation 
  or 
  intermingling. 
  This 
  

   coarse 
  sand 
  passes 
  quickly 
  up 
  into 
  an 
  unstratified 
  mass 
  of 
  loose 
  

  

  