﻿ON 
  THE 
  CRAG-SHELL 
  GRAVEL 
  BEDS 
  OE 
  ABERDEENSHIRE. 
  145 
  

  

  15. 
  On 
  the 
  Crag 
  Shells 
  of 
  Aberdeenshire 
  and 
  the 
  Gravel-beds 
  

   containing 
  them. 
  By 
  Thomas 
  F. 
  Jamteson, 
  Esq., 
  F.G.S. 
  (Read 
  

   March 
  8, 
  1882.) 
  

  

  Contents. 
  

  

  Introductory. 
  

  

  Extent 
  and 
  Distribution 
  of 
  the 
  Gravel. 
  

  

  Internal 
  Structure 
  and 
  Contents 
  of 
  the 
  Gravel 
  Ridges. 
  

  

  The 
  Coast 
  Section. 
  

  

  Order 
  of 
  Succession 
  and 
  Derivation 
  of 
  the 
  Beds. 
  

  

  List 
  of 
  Shells, 
  with 
  Remarks 
  on 
  the 
  Species. 
  

  

  Details 
  of 
  a 
  few 
  Sections 
  along 
  the 
  Coast 
  of 
  Slains. 
  

  

  In 
  the 
  year 
  1860 
  I 
  sent 
  to 
  the 
  Geological 
  Society 
  a 
  short 
  notice 
  of 
  

   certain 
  beds 
  of 
  sand 
  and 
  gravel 
  on 
  the 
  eastern 
  border 
  of 
  Aberdeen- 
  

   shire, 
  which 
  I 
  had 
  found 
  to 
  contain 
  fragments 
  of 
  shells 
  resembling 
  

   those 
  met 
  with 
  in 
  the 
  Crag 
  strata 
  of 
  Norfolk. 
  These 
  shells 
  are 
  much 
  

   broken 
  and 
  worn 
  — 
  most 
  of 
  them 
  mere 
  crumbs 
  ; 
  and 
  few 
  are 
  in 
  a 
  

   condition 
  to 
  enable 
  even 
  a 
  skilful 
  conchologist 
  to 
  pronounce 
  with 
  

   certainty 
  as 
  to 
  their 
  specific 
  character, 
  although 
  it 
  is 
  sufficiently 
  

   clear 
  that 
  they 
  represent 
  a 
  considerable 
  variety 
  of 
  forms. 
  Never- 
  

   theless 
  characteristic 
  specimens 
  distinct 
  enough 
  for 
  identification 
  are 
  

   occasionally 
  got. 
  

  

  The 
  Messrs. 
  Searles 
  Y. 
  Wood, 
  senior 
  and 
  junior, 
  who 
  twice 
  exa- 
  

   mined 
  my 
  collection, 
  confirmed 
  my 
  opinion 
  as 
  to 
  the 
  Crag 
  character 
  

   of 
  several 
  of 
  the 
  species 
  ; 
  and 
  Dr. 
  Gwyn 
  Jeffreys, 
  who 
  looked 
  at 
  

   them 
  in 
  passing 
  here 
  a 
  good 
  many 
  years 
  ago, 
  came 
  to 
  the 
  same 
  con- 
  

   clusion. 
  The 
  shells 
  have 
  a 
  decidedly 
  older 
  and 
  more 
  fossilized 
  

   appearance 
  than 
  those 
  from 
  our 
  Scotch 
  glacial 
  beds 
  ; 
  and 
  some 
  

   of 
  them 
  are 
  filled 
  with 
  a 
  hard 
  calcareous 
  paste 
  or 
  concrete, 
  which 
  is 
  

   another 
  feature 
  that 
  serves 
  to 
  distinguish 
  them. 
  

  

  My 
  residence 
  in 
  the 
  neighbourhood 
  has 
  given 
  me 
  many 
  oppor- 
  

   tunities 
  of 
  studying 
  the 
  subject 
  more 
  perfectly 
  since 
  my 
  former 
  

   communications 
  to 
  the 
  Society 
  : 
  and 
  as 
  frequent 
  reference 
  has 
  been 
  

   made 
  to 
  these 
  gravel-beds 
  by 
  Mr. 
  Searles 
  V. 
  Wood, 
  and 
  others, 
  and 
  

   as 
  a 
  good 
  deal 
  of 
  doubt 
  has 
  arisen 
  as 
  to 
  their 
  true 
  age 
  and 
  position, 
  

   I 
  shall 
  in 
  the 
  following 
  pages 
  point 
  out 
  their 
  exact 
  place 
  in 
  the 
  

   series 
  of 
  superficial 
  beds 
  and 
  give 
  a 
  list 
  of 
  all 
  the 
  shells 
  that 
  have 
  

   been 
  identified 
  from 
  them. 
  

  

  Although 
  no 
  doubt 
  could 
  be 
  entertained 
  that 
  the 
  shells 
  them- 
  

   selves 
  were 
  older 
  than 
  those 
  previously 
  reported 
  from 
  any 
  of 
  our 
  

   Scotch 
  glacial 
  beds, 
  it 
  was 
  by 
  no 
  means 
  so 
  clear 
  what 
  was 
  the 
  age 
  of 
  

   the 
  gravel 
  containing 
  them. 
  Judging 
  from 
  its 
  fossil 
  contents 
  and 
  

   from 
  certain 
  other 
  circumstances, 
  I 
  at 
  one 
  time 
  thought 
  that 
  some 
  

   part 
  at 
  least 
  of 
  the 
  gravel 
  itself 
  might 
  be 
  a 
  preglacial 
  deposit 
  

   of 
  Crag 
  age 
  ; 
  but 
  I 
  afterwards 
  ascertained 
  that 
  what 
  appears 
  to 
  be 
  

   a 
  glacial 
  bed 
  underlies 
  it, 
  and 
  I 
  therefore 
  now 
  believe 
  that 
  in 
  their 
  

   present 
  state 
  these 
  accumulations 
  are 
  really 
  all 
  of 
  more 
  recent 
  

   origin 
  than 
  their 
  fossil 
  contents 
  would 
  indicate, 
  and 
  that 
  the 
  shells, 
  

  

  