﻿OF 
  THE 
  ABERDEENSHIRE 
  COAST. 
  173 
  

  

  C.E., 
  Inverness, 
  at 
  Clava 
  in 
  the 
  valley 
  of 
  the 
  Nairn, 
  at 
  an 
  altitude 
  of 
  

   500 
  feet, 
  which 
  shows 
  v 
  that 
  a 
  similar 
  amountof 
  submergence 
  must 
  

   have 
  taken 
  place 
  in 
  that 
  district. 
  

  

  11. 
  Geological 
  Date 
  of 
  the 
  Submergence. 
  

  

  AVe 
  have 
  seen 
  that 
  the 
  Red 
  Clay 
  was 
  laid 
  down 
  before 
  the 
  last 
  

   great 
  advance 
  of 
  the 
  glaciers, 
  and 
  that 
  the 
  submergence 
  to 
  which 
  it 
  

   is 
  due 
  followed 
  upon 
  a 
  previous 
  development 
  of 
  the 
  ice 
  of 
  far 
  greater 
  

   amount. 
  This 
  earlier 
  glaciation 
  seems 
  to 
  have 
  been 
  extremely 
  

   intense 
  and 
  long-continued 
  ; 
  for 
  it 
  has 
  well 
  nigh 
  effaced 
  all 
  pre- 
  

   existing 
  records 
  which 
  would 
  have 
  thrown 
  light 
  upon 
  the 
  antecedent 
  

   history 
  of 
  the 
  surface. 
  How 
  long 
  it 
  endured, 
  and 
  whether 
  there 
  

   were 
  other 
  periods 
  of 
  glaciation 
  before 
  it 
  with 
  intervals 
  of 
  milder 
  

   climate, 
  as 
  some 
  suppose, 
  are 
  questions 
  to 
  which 
  no 
  satisfactory 
  

   answer 
  has 
  as 
  yet 
  been 
  got 
  from 
  the 
  evidence 
  in 
  this 
  part 
  of 
  

   Scotland. 
  

  

  The 
  Mollusca 
  whose 
  shells 
  are 
  found 
  in 
  the 
  clay 
  all 
  belong 
  to 
  

   existing 
  species 
  now 
  living 
  in 
  the 
  Northern 
  seas 
  ; 
  and 
  in 
  this 
  respect 
  

   they 
  resemble 
  those 
  got 
  in 
  the 
  other 
  arctic 
  shell-beds 
  of 
  the 
  East 
  

   of 
  Scotland, 
  and 
  differ 
  as 
  a 
  group 
  from 
  those 
  found 
  in 
  the 
  Bridling- 
  

   ton 
  shell-bed 
  of 
  the 
  Yorkshire 
  coast, 
  and 
  also 
  from 
  those 
  re- 
  

   ported 
  by 
  Mr. 
  S. 
  V. 
  Wood 
  from 
  what 
  he 
  terms 
  the 
  Middle 
  Glacial 
  

   Sands 
  of 
  England, 
  both 
  of 
  which 
  contain 
  some 
  species 
  that 
  are 
  

   extinct, 
  or 
  at 
  all 
  events 
  unknown 
  in 
  the 
  Northern 
  or 
  British 
  seas. 
  

   Our 
  submergence 
  must 
  therefore 
  be 
  of 
  later 
  date. 
  The 
  Aberdeen- 
  

   shire 
  group 
  seems 
  more 
  allied 
  to 
  those 
  reported 
  by 
  Mr. 
  Prestwich 
  

   from 
  the 
  Kelsea-Hill 
  Gravel 
  in 
  Yorkshire 
  (see 
  Quart. 
  Journ. 
  Geol. 
  

   Soc. 
  for 
  April 
  1861, 
  vol. 
  xvii. 
  p. 
  446), 
  and 
  to 
  the 
  shells 
  from 
  the 
  

   Glacial 
  clays 
  of 
  Lancashire. 
  

  

  Dr. 
  James 
  Geikie, 
  in 
  his 
  recent 
  able 
  work 
  on 
  Prehistoric 
  Europe, 
  

   has 
  referred 
  the 
  Errol 
  and 
  Montrose 
  clays 
  to 
  a 
  still 
  later 
  period. 
  

   He 
  terms 
  them 
  Estuarine 
  clays, 
  and 
  supposes 
  them 
  to 
  have 
  been 
  

   laid 
  down 
  after 
  the 
  last 
  ice 
  sheet 
  had 
  passed 
  away, 
  at 
  a 
  time 
  when 
  

   he 
  thinks 
  a 
  subsequent 
  submergence 
  of 
  the 
  Scottish 
  coast 
  took 
  place 
  

   to 
  the 
  extent 
  of 
  90 
  feet. 
  I 
  cannot 
  say 
  that 
  I 
  have 
  found 
  any 
  

   evidence 
  on 
  the 
  Aberdeenshire 
  coast 
  of 
  a 
  subsequent 
  submergence 
  

   to 
  this 
  extent 
  ; 
  and 
  it 
  seems 
  to 
  me 
  that 
  the 
  groups 
  of 
  shells 
  found 
  

   both 
  at 
  Errol 
  and 
  Montrose 
  infer 
  both 
  an 
  earlier 
  date 
  and 
  a 
  much 
  

   greater 
  amount 
  of 
  submergence. 
  The 
  Mollusca 
  are 
  a 
  deep-water 
  

   group, 
  and 
  not 
  an 
  estuarine 
  assemblage. 
  The 
  Errol 
  shell-bed 
  at 
  

   present 
  lies 
  40 
  feet 
  above 
  the 
  sea. 
  A 
  submergence 
  of 
  90 
  feet 
  

   would 
  therefore 
  place 
  it 
  under 
  50 
  feet 
  of 
  water, 
  which 
  is 
  little 
  

   more 
  than 
  8 
  fathoms. 
  Now 
  this 
  does 
  not 
  at 
  all 
  harmonize 
  with 
  the 
  

   character 
  of 
  the 
  group. 
  The 
  Rev. 
  Mr. 
  Brown 
  (who 
  had 
  the 
  

   assistance 
  of 
  Dr. 
  Otto 
  Torell 
  in 
  regard 
  to 
  the 
  shells), 
  in 
  his 
  paper 
  on 
  

   the 
  subject 
  in 
  the 
  Trans, 
  of 
  the 
  Roy. 
  Soc. 
  of 
  Edin. 
  vol. 
  xxiv. 
  p. 
  630, 
  

   concludes 
  that 
  " 
  the 
  level 
  of 
  the 
  land 
  was 
  at 
  least 
  150 
  to 
  200 
  feet 
  

   lower 
  than 
  now 
  ;" 
  and, 
  so 
  far 
  as 
  I 
  can 
  form 
  an 
  opinion 
  from 
  the 
  

   organic 
  evidence, 
  I 
  should 
  say 
  the 
  probability 
  is 
  in 
  favour 
  of 
  a 
  

  

  