﻿OF 
  THE 
  ABEKDEENSHIRE 
  COAST. 
  169 
  

  

  withdrew 
  to 
  the 
  region 
  whence 
  it 
  set 
  out 
  ; 
  for 
  we 
  find 
  the 
  Red 
  

   Clay 
  covering 
  some 
  of 
  the 
  low 
  coast-districts 
  of 
  Kincardine, 
  Forfar, 
  

   Perth, 
  and 
  Pile, 
  there 
  being 
  beds 
  of 
  it 
  at 
  Montrose 
  and 
  Errol 
  con- 
  

   taining 
  marine 
  shells 
  and 
  starfishes 
  in 
  situ, 
  which 
  proves 
  that 
  the 
  

   ice 
  had 
  retired 
  and 
  the 
  sea 
  had 
  taken 
  its 
  place. 
  This 
  submergence 
  

   may 
  be 
  traced 
  across 
  Scotland 
  south-westward 
  to 
  the 
  neighbourhood 
  

   of 
  Loch 
  Lomond, 
  near 
  which 
  we 
  find, 
  at 
  Balfron 
  and 
  elsewhere, 
  beds 
  

   of 
  the 
  very 
  same 
  sort 
  of 
  red 
  clay, 
  derived 
  from 
  the 
  sandstone 
  of 
  that 
  

   quarter, 
  not 
  far 
  from 
  the 
  base 
  of 
  Benlomond, 
  which 
  shows 
  that 
  the 
  

   glaciers 
  had 
  vanished 
  from 
  the 
  low 
  ground 
  of 
  Scotland 
  at 
  this 
  

   time. 
  

  

  If 
  I 
  am 
  right 
  in 
  my 
  explanation 
  of 
  the 
  origin 
  of 
  the 
  Red 
  Clay 
  and 
  

   the 
  way 
  in 
  which 
  the 
  glacier 
  retired, 
  we 
  may 
  infer 
  that 
  the 
  clay- 
  

   beds 
  at 
  Errol 
  and 
  Montrose 
  were 
  deposited 
  at 
  a 
  somewhat 
  later 
  

   date 
  than 
  the 
  earliest 
  of 
  those 
  on 
  the 
  Aberdeenshire 
  coast. 
  There 
  

   would 
  in 
  fact 
  be 
  a 
  gradual 
  succession 
  of 
  the 
  beds 
  deposited 
  as 
  we 
  

   trace 
  them 
  from 
  Peterhead 
  back 
  to 
  Aberdeen, 
  Stonehaven, 
  Montrose, 
  

   and 
  Errol, 
  while 
  that 
  near 
  Benlomond 
  would 
  probably 
  be 
  the 
  latest 
  

   of 
  aU. 
  

  

  As 
  these 
  marine 
  beds 
  have 
  suffered 
  much 
  denudation 
  from 
  a 
  

   subsequent 
  advance 
  of 
  the 
  glaciers 
  and 
  other 
  causes, 
  the 
  upper 
  strata 
  

   are 
  probably 
  wanting, 
  and 
  we 
  have 
  a 
  blank 
  in 
  the 
  evidence 
  at 
  the 
  

   next 
  stage. 
  Here 
  may 
  have 
  occurred 
  a 
  long 
  interval 
  of 
  time 
  during 
  

   which 
  one 
  of 
  those 
  warmer 
  periods 
  intervened 
  when 
  some 
  of 
  the 
  

   Mammalia 
  flourished 
  whose 
  remains 
  are 
  found 
  in 
  the 
  caves 
  and 
  river- 
  

   beds 
  of 
  England. 
  

  

  7. 
  Northern 
  Limit 
  op 
  the 
  Red 
  Clay 
  and 
  of 
  the 
  Ice-flow. 
  

  

  Blue 
  clay 
  of 
  the 
  Banffshire 
  coast. 
  

  

  During 
  the 
  extension 
  of 
  the 
  ice 
  along 
  the 
  coast 
  it 
  is 
  probable 
  that 
  

   it 
  underwent 
  phases 
  of 
  increase 
  and 
  diminution, 
  like 
  all 
  existing 
  

   glaciers. 
  We 
  are 
  apt 
  to 
  take 
  too 
  narrow 
  and 
  simple 
  a 
  view 
  of 
  the 
  

   changes 
  that 
  have 
  happened 
  during 
  the 
  long 
  periods 
  these 
  operations 
  

   of 
  nature 
  embrace. 
  In 
  some 
  of 
  the 
  deeper 
  sections 
  near 
  Peterhead 
  

   there 
  are 
  indications 
  of 
  considerable 
  variety 
  in 
  the 
  character 
  of 
  

   the 
  clay. 
  Beds 
  of 
  a 
  fine 
  dark-blue 
  clay 
  occur 
  interstratified 
  with 
  

   the 
  red, 
  which 
  imply 
  derivation 
  from 
  a 
  different 
  source. 
  Round 
  the 
  

   northern 
  extremity 
  of 
  Aberdeenshire 
  and 
  along 
  the 
  coast 
  of 
  Banff 
  

   there 
  is 
  a 
  deposit 
  of 
  this 
  blackish-blue 
  or 
  indigo-coloured 
  clay, 
  which 
  

   seems 
  to 
  have 
  been 
  derived 
  from 
  the 
  dark 
  slaty 
  rocks 
  of 
  the 
  Banffshire 
  

   district, 
  and 
  has 
  been 
  carried 
  eastward 
  round 
  the 
  projecting 
  corner 
  

   of 
  Aberdeenshire 
  until 
  it 
  met 
  the 
  red 
  clay 
  in 
  the 
  district 
  between 
  

   Peterhead 
  and 
  Eraserburgh. 
  

  

  The 
  ice 
  of 
  the 
  Moray 
  Firth 
  seems 
  to 
  have 
  flowed 
  eastward 
  along 
  

   the 
  Banffshire 
  coast 
  and 
  turned 
  round 
  the 
  corner 
  of 
  Aberdeenshire 
  

   at 
  Fraserburgh, 
  where 
  the 
  rocks 
  are 
  glaciated 
  from 
  the 
  north-west; 
  

   so 
  that 
  there 
  seem 
  to 
  have 
  been 
  two 
  streams 
  of 
  ice 
  — 
  one 
  coming 
  

   along 
  the 
  coast 
  from 
  the 
  Moray 
  Firth, 
  bringing 
  with 
  it 
  the 
  blue 
  mud 
  

  

  n 
  2 
  

  

  