﻿OP 
  THE 
  ABERDEENSHIRE 
  COAST. 
  171 
  

  

  ground 
  called 
  ' 
  the 
  Long 
  Forties,' 
  which 
  extends 
  from 
  opposite 
  the 
  

   Firth 
  of 
  Tay 
  in 
  a 
  BT.E. 
  direction 
  to 
  opposite 
  Kinnaird's 
  Head. 
  Between 
  

   this 
  bank 
  and 
  the 
  present 
  coast-line 
  there 
  is 
  a 
  long 
  hollow 
  called 
  " 
  the 
  

   Buchan 
  deeps," 
  which 
  stretches 
  in 
  a 
  parallel 
  line 
  from 
  near 
  Montrose 
  

   to 
  opposite 
  Kinnaird's 
  Head, 
  deepening 
  very 
  gradually 
  from 
  south 
  

   to 
  north. 
  This 
  hollow 
  may 
  represent 
  the 
  central 
  path 
  of 
  the 
  ice- 
  

   stream 
  which 
  grazed 
  the 
  Aberdeenshire 
  coast, 
  while 
  the 
  Long 
  Forties, 
  

   may 
  mark 
  its 
  eastern 
  flank. 
  

  

  9. 
  Reappearance 
  oe 
  the 
  Glaciers, 
  and 
  Denudation 
  oe 
  the 
  

   Red 
  Clay. 
  

  

  There 
  is 
  evidence 
  that 
  at 
  some 
  period 
  after 
  the 
  Red 
  Clay 
  had 
  been 
  

   laid 
  down, 
  the 
  glaciers 
  from 
  the 
  interior 
  again 
  advanced 
  and 
  swept 
  

   most 
  of 
  it 
  away 
  along 
  the 
  track 
  of 
  the 
  principal 
  ice-streams. 
  In 
  the 
  

   valley 
  of 
  the 
  Dee 
  the 
  ice 
  came 
  down 
  from 
  the 
  mountains 
  to 
  the 
  

   present 
  line 
  of 
  coast, 
  and, 
  uniting 
  probably 
  with 
  that 
  of 
  the 
  Don 
  

   valley, 
  presented 
  a 
  front 
  at 
  least 
  five 
  miles 
  broad, 
  leaving 
  great 
  

   mounds 
  of 
  gravel 
  and 
  stones 
  all 
  along 
  its 
  margin 
  (see 
  map, 
  p. 
  161). 
  

   This 
  moraine-gravel 
  distinctly 
  overlies 
  the 
  Red 
  Clay 
  at 
  its 
  termina- 
  

   tion. 
  The 
  clay 
  is 
  entirely 
  absent 
  from 
  the 
  valleys 
  both 
  of 
  the 
  Dee 
  and 
  

   Don, 
  only 
  a 
  few 
  small 
  deep-lying 
  patches 
  being 
  left 
  near 
  the 
  town 
  

   of 
  Aberdeen 
  ; 
  while 
  immediately 
  to 
  the 
  north 
  of 
  these 
  moraines, 
  on 
  

   the 
  coast 
  at 
  Belhelvie, 
  the 
  red 
  clay 
  begins 
  at 
  once 
  to 
  reappear 
  exactly 
  

   where 
  the 
  gravel 
  ceases, 
  covering 
  the 
  fields 
  beyond 
  the 
  Burn 
  of 
  

   Milden 
  to 
  the 
  height 
  of 
  200 
  feet 
  or 
  more 
  above 
  the 
  sea 
  ; 
  and 
  along 
  

   the 
  south 
  bank 
  of 
  that 
  streamlet 
  the 
  superposition 
  of 
  the 
  moraine 
  

   gravel 
  upon 
  the 
  wasted 
  margin 
  of 
  the 
  clay 
  can 
  be 
  clearly 
  made 
  out. 
  

   This 
  gravel 
  also 
  occasionally 
  contains 
  wasted 
  lumps 
  of 
  the 
  clay, 
  and 
  

   confused 
  masses 
  of 
  the 
  silty 
  beds 
  are 
  sometimes 
  jumbled 
  up 
  with 
  it, 
  

   as 
  at 
  the 
  north 
  side 
  of 
  the 
  Bay 
  of 
  ISTigg 
  near 
  Aberdeen. 
  The 
  morainic 
  

   character 
  of 
  the 
  gravel 
  is 
  very 
  well 
  seen 
  at 
  the 
  top 
  of 
  the 
  mud 
  clifT 
  

   at 
  the 
  south 
  side 
  of 
  the 
  same 
  bay 
  (fig. 
  3, 
  p. 
  175). 
  

  

  Owing 
  to 
  this 
  new 
  advance 
  of 
  the 
  glaciers, 
  which 
  no 
  doubt 
  coin- 
  

   cided 
  with 
  the 
  return 
  of 
  a 
  more 
  rigorous 
  climate, 
  the 
  marine 
  beds 
  

   have 
  been 
  much 
  destroyed. 
  In 
  many 
  places 
  they 
  have 
  been 
  entirely 
  

   removed 
  ; 
  in 
  others 
  the 
  upper 
  portion 
  has 
  been 
  swept 
  off, 
  or 
  converted 
  

   into 
  an 
  unstratified 
  pebbly 
  mud 
  ; 
  while 
  in 
  others, 
  again, 
  they 
  have 
  

   been 
  pushed 
  out 
  of 
  place 
  or 
  their 
  stratification 
  has 
  been 
  contorted 
  

   and 
  more 
  or 
  less 
  deranged 
  by 
  the 
  pressure 
  of 
  the 
  ice. 
  The 
  proba- 
  

   bility 
  therefore 
  is 
  that 
  the 
  uppermost 
  or 
  last-deposited 
  portion 
  of 
  

   these 
  marine 
  beds 
  is 
  everywhere 
  gone. 
  

  

  10. 
  Upper 
  Limit 
  of 
  the 
  Submergence. 
  

  

  The 
  upper 
  limit 
  of 
  the 
  submergence 
  during 
  which 
  the 
  Red 
  Clay 
  

   was 
  deposited 
  cannot 
  at 
  present 
  be 
  determined. 
  The 
  readvance 
  of 
  

   the 
  ice 
  has 
  blotted 
  out 
  the 
  evidence. 
  The 
  clay 
  itself 
  with 
  a 
  well- 
  

   defined 
  character 
  ranges 
  up 
  to 
  at 
  least 
  300 
  feet 
  above 
  the 
  sea 
  in 
  

   the 
  Ellon 
  district, 
  being 
  found 
  stretching 
  continuously 
  up 
  to 
  the 
  top 
  

   of 
  some 
  eminences 
  at 
  that 
  elevation 
  on 
  the 
  estate 
  of 
  Kinmuck 
  and 
  

  

  