﻿160 
  T. 
  P. 
  JAMIESON 
  ON 
  THE 
  RED 
  CLAY 
  OP 
  ABERDEENSHIRE. 
  

  

  16. 
  On 
  ^Bed 
  Clay 
  of 
  the 
  Aberdeenshire 
  Coast 
  and 
  the 
  Direction 
  

   of 
  the 
  Ice-moyement 
  in 
  that 
  quarter. 
  By 
  Thomas 
  F. 
  Jamieson, 
  

   Esq., 
  F.G.S. 
  (Bead 
  March 
  8, 
  1882.) 
  

  

  Contents. 
  

  

  1. 
  General 
  Distribution 
  and 
  Character 
  of 
  the 
  Clay. 
  

  

  2. 
  Its 
  Mineral 
  Contents. 
  

  

  3. 
  Drift 
  from 
  the 
  Southward. 
  

  

  4. 
  Change 
  of 
  Direction 
  in 
  the 
  Ice-flow. 
  

  

  5. 
  Organic 
  Contents 
  of 
  the 
  Clay. 
  

  

  6. 
  Progress 
  of 
  the 
  Submergence. 
  

  

  7. 
  Northern 
  Limit 
  of 
  the 
  Red 
  Clay. 
  Blue 
  Clay 
  of 
  the 
  Banffshire 
  coast. 
  

  

  8. 
  Direction 
  of 
  the 
  Ice-flow 
  to 
  the 
  South 
  of 
  Stonehaven. 
  

  

  9. 
  Reappearance 
  of 
  the 
  Glaciers, 
  and 
  Denudation 
  of 
  the 
  Red 
  Clay. 
  

  

  10. 
  Upper 
  Limit 
  of 
  the 
  Submergence. 
  

  

  11. 
  Geological 
  Date 
  of 
  the 
  Submergence. 
  

  

  12. 
  Explanation 
  of 
  the 
  Section 
  at 
  the 
  Bay 
  of 
  Nigg. 
  

  

  1. 
  General 
  Distribution 
  and 
  Character 
  op 
  the 
  Clay. 
  

  

  The 
  more 
  we 
  know 
  of 
  the 
  Glacial 
  period 
  the 
  more 
  evident 
  it 
  becomes 
  

   that 
  it 
  embraces 
  a 
  long 
  and 
  complicated 
  series 
  of 
  changes 
  which 
  

   will 
  require 
  much 
  patient 
  study 
  to 
  understand 
  ; 
  and 
  some 
  districts 
  

   are 
  found 
  valuable 
  as 
  presenting 
  clear 
  evidence 
  of 
  certain 
  events 
  

   which 
  cannot 
  be 
  discovered 
  from 
  the 
  appearances 
  we 
  find 
  in 
  other 
  

   quarters. 
  

  

  The 
  Aberdeenshire 
  coast 
  is 
  one 
  of 
  those 
  districts. 
  On 
  the 
  eastern 
  

   side 
  of 
  that 
  county 
  we 
  find 
  a 
  well-marked 
  bed 
  of 
  red 
  clay, 
  which 
  

   covers 
  much 
  of 
  the 
  low 
  ground 
  along 
  the 
  coast 
  between 
  Aberdeen 
  

   and 
  Peterhead, 
  and 
  extends 
  some 
  distance 
  to 
  the 
  north 
  of 
  the 
  latter 
  

   town 
  (see 
  Map, 
  fig. 
  1). 
  It 
  ranges 
  from 
  the 
  sea-level 
  up 
  to 
  an 
  altitude 
  

   of 
  300 
  feet, 
  but 
  is 
  scarcely 
  seen 
  at 
  heights 
  beyond 
  that, 
  although 
  there 
  

   are 
  here 
  and 
  there 
  some 
  indications 
  of 
  it 
  at 
  a 
  higher 
  level. 
  It 
  stretches 
  

   inland 
  along 
  the 
  course 
  of 
  the 
  various 
  streamlets 
  which 
  come 
  down 
  

   to 
  the 
  coast, 
  and 
  appears 
  to 
  have 
  subsided 
  most 
  thickly 
  in 
  the 
  depres- 
  

   sions 
  that 
  intervene 
  between 
  the 
  low 
  eminences 
  of 
  gneiss 
  and 
  granite 
  

   which 
  constitute 
  the 
  rocky 
  framework 
  of 
  the 
  district. 
  In 
  some 
  of 
  

   these 
  depressions 
  patches 
  of 
  it 
  are 
  found 
  of 
  great 
  thickness 
  and 
  

   purity. 
  A 
  depth 
  of 
  twenty 
  or 
  thirty 
  feet 
  may 
  occur 
  in 
  which 
  few 
  

   stones 
  or 
  pebbles 
  of 
  any 
  kind 
  are 
  to 
  be 
  seen. 
  These 
  masses, 
  however, 
  

   are 
  usually 
  of 
  very 
  limited 
  extent 
  ; 
  and 
  commonly 
  the 
  clay 
  is 
  much 
  

   thinner 
  and 
  coarser, 
  with 
  some 
  pebbles 
  and 
  occasionally 
  large 
  boulders 
  

   interspersed 
  through 
  it, 
  while 
  sometimes 
  it 
  is 
  so 
  coarse 
  as 
  to 
  assume 
  

   the 
  character 
  of 
  a 
  Boulder-clay. 
  The 
  finer 
  kinds 
  of 
  it 
  are 
  often 
  

   delicately 
  laminated, 
  and 
  occasionally 
  pass 
  gradually 
  into 
  beds 
  of 
  a 
  

   more 
  sandy 
  nature, 
  or 
  have 
  seams 
  of 
  sand 
  interstratified 
  with 
  them. 
  

  

  Now 
  this 
  clay 
  is 
  not 
  such 
  a 
  deposit 
  as 
  would 
  be 
  derived 
  from 
  the 
  

   rocks 
  of 
  the 
  district 
  in 
  which 
  it 
  occurs 
  ; 
  for 
  the 
  grinding 
  down 
  of 
  the 
  

   gneiss 
  and 
  granite 
  gives 
  rise 
  to 
  sediment 
  of 
  a 
  grey 
  colour, 
  generally 
  

   somewhat 
  bluish-grey 
  where 
  the 
  gneiss 
  predominates, 
  and 
  of 
  a 
  more 
  

   brownish 
  tint 
  where 
  the 
  granite 
  prevails. 
  This 
  is 
  well 
  seen 
  from 
  

   the 
  nature 
  of 
  the 
  Boulder-clay 
  covering 
  these 
  rocks, 
  and 
  which 
  has 
  

  

  