﻿THE 
  GLACIAL 
  PERIOD 
  IN 
  NORTH 
  BRITAIN. 
  321 
  

  

  glen, 
  in 
  the 
  cliffs 
  facing 
  the 
  sea. 
  I 
  regret 
  having 
  been 
  prevented 
  

   from 
  tracing 
  the 
  outline 
  of 
  this 
  peculiar 
  fossiliferous 
  drift 
  of 
  Caith- 
  

   ness 
  along 
  all 
  its 
  western 
  boundary 
  ; 
  for 
  features 
  of 
  interest 
  will 
  no 
  

   doubt 
  present 
  themselves 
  where 
  the 
  ice 
  from 
  the 
  hilly 
  ground 
  came 
  

   down 
  upon 
  it. 
  

  

  From 
  Berriedale 
  to 
  Inverness, 
  all 
  along 
  the 
  eastern 
  border 
  of 
  

   Sutherland 
  and 
  Boss, 
  the 
  later 
  glaciers 
  seem 
  everywhere 
  to 
  have 
  

   come 
  down 
  in 
  great 
  force 
  to 
  the 
  present 
  coast-line. 
  At 
  Ardersier, 
  

   near 
  Fort 
  George, 
  I 
  came 
  upon 
  a 
  small 
  patch, 
  a 
  few 
  yards 
  in 
  extent, 
  

   of 
  grey 
  clay, 
  containing 
  arctic 
  sea-shells. 
  It 
  was 
  buried 
  underneath, 
  

   or 
  enveloped 
  in, 
  a 
  brownish 
  unfossiliferous 
  mass 
  of 
  gravel 
  and 
  silt, 
  

   and 
  seemed 
  to 
  be 
  a 
  remnant 
  of 
  some 
  bed 
  that 
  had 
  been 
  destroyed 
  

   by 
  the 
  action 
  of 
  the 
  later 
  glaciers. 
  Its 
  occurrence, 
  however, 
  in- 
  

   terested 
  me 
  much, 
  by 
  showing 
  that 
  glacial 
  marine 
  deposits 
  had 
  once 
  

   existed 
  in 
  that 
  neighbourhood. 
  Although 
  no 
  marine 
  fossils 
  were 
  

   got 
  in 
  the 
  cuttings 
  for 
  the 
  Caledonian 
  Canal, 
  it 
  is 
  worthy 
  of 
  note 
  

   that 
  they 
  have 
  now 
  been 
  discovered 
  near 
  Fort 
  William 
  and 
  Fort 
  

   George, 
  at 
  both 
  extremities 
  of 
  the 
  great 
  glen. 
  

  

  Glacial 
  clays 
  containing 
  marine 
  fossils 
  of 
  arctic 
  type 
  are 
  scarcely 
  

   known 
  along 
  the 
  borders 
  of 
  the 
  Moray 
  Firth. 
  Dr. 
  Gordon, 
  of 
  Birnie, 
  

   tells 
  me 
  the 
  only 
  instances 
  he 
  is 
  aware 
  of 
  are 
  this 
  one 
  at 
  Ardersier 
  

   and 
  another 
  at 
  Burghead. 
  Iu 
  the 
  interior 
  of 
  JS"airn 
  and 
  Elgin 
  they 
  

   have 
  not 
  been 
  found. 
  

  

  I 
  met 
  with 
  them, 
  however, 
  some 
  distance 
  to 
  the 
  east 
  of 
  Spey- 
  

   mouth, 
  between 
  Cullen 
  and 
  Banff, 
  where 
  the 
  sea-cliffs 
  here 
  and 
  

   there 
  show 
  deep 
  masses 
  of 
  dark 
  bluish 
  clay, 
  in 
  which 
  remains 
  of 
  

   arctic 
  shells 
  may 
  occasionally 
  be 
  detected. 
  Further 
  eastward, 
  at 
  

   Gamrie, 
  they 
  again 
  present 
  themselves, 
  but 
  only 
  to 
  a 
  very 
  limited 
  

   extent, 
  having 
  apparently 
  been 
  swept 
  out 
  of 
  the 
  little 
  ravines 
  by 
  

   small 
  glaciers 
  descending 
  from 
  the 
  neighbouring 
  heights. 
  Without 
  

   this 
  hypothesis 
  it 
  is 
  difficult 
  to 
  account 
  for 
  the 
  patchy 
  manner 
  in 
  

   which 
  these 
  marine 
  beds 
  have 
  been 
  left 
  there. 
  

  

  In 
  the 
  island 
  of 
  Arran, 
  as 
  has 
  been 
  shown 
  by 
  the 
  Bev. 
  Mr. 
  

   Watson 
  and 
  Dr. 
  Bryce, 
  we 
  have 
  evidence 
  of 
  submergence 
  to 
  the 
  

   amount 
  of 
  some 
  hundreds 
  of 
  feet 
  above 
  the 
  present 
  sea-level 
  ; 
  but 
  

   the 
  marine 
  beds 
  have 
  all 
  disappeared 
  from 
  the 
  mountainous 
  part 
  of 
  

   the 
  island, 
  and 
  even 
  in 
  the 
  lower 
  southern 
  extremity 
  they 
  have 
  been 
  

   wellnigh 
  destroyed 
  and 
  overwhelmed 
  beneath 
  heavy 
  masses 
  of 
  sand, 
  

   mud 
  and 
  boulders 
  — 
  the 
  work, 
  as 
  I 
  suppose, 
  of 
  the 
  later 
  glaciers. 
  

  

  Long 
  ago 
  Dr. 
  Scouler 
  pointed 
  out 
  that 
  certain 
  ravines 
  near 
  

   Dublin 
  had 
  apparently 
  been 
  formed 
  after 
  the 
  deposition 
  of 
  the 
  shelly 
  

   gravel 
  of 
  that 
  district, 
  from 
  the 
  fact 
  that 
  they 
  are 
  completely 
  desti- 
  

   tute 
  of 
  any 
  vestige 
  of 
  this 
  marine 
  gravel, 
  although 
  it 
  ascends 
  to 
  

   higher 
  levels 
  in 
  the 
  neighbourhood. 
  But 
  he 
  was 
  at 
  a 
  loss 
  to 
  under- 
  

   stand 
  on 
  what 
  principle 
  of 
  selection 
  one 
  set 
  of 
  hollows 
  had 
  become 
  

   receptacles 
  of 
  this 
  shelly 
  drift 
  while 
  others 
  had 
  escaped 
  (Journ. 
  of 
  

   Geol. 
  Soc. 
  of 
  Dublin, 
  vol. 
  i. 
  p. 
  266). 
  Afterwards 
  Mr. 
  Oldham, 
  in 
  1848, 
  

   in 
  examining 
  this 
  locality 
  and 
  confirming 
  Dr. 
  Scouler's 
  observations, 
  

   was 
  struck 
  with 
  the 
  same 
  remarkable 
  fact, 
  that 
  several 
  of 
  the 
  glens 
  

   in 
  Wicklow 
  contain 
  no 
  trace 
  of 
  marine 
  beds, 
  although 
  shelly 
  gravels 
  

  

  