﻿OF 
  THE 
  ABEKDEENSHIKE 
  COAST. 
  175 
  

  

  The 
  section 
  which, 
  is 
  so 
  well 
  exposed 
  in 
  the 
  mud 
  cliff 
  facing 
  the 
  

   sea 
  at 
  the 
  south 
  side 
  of 
  the 
  Bay 
  of 
  Nigg 
  (fig. 
  3) 
  is 
  so 
  instructive 
  as 
  to 
  

   merit 
  a 
  detailed 
  description. 
  

  

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

  

  Pig. 
  3. 
  — 
  Section 
  of 
  Mud 
  Cliff 
  at 
  Bay 
  of 
  Nigg. 
  

   (Depth 
  of 
  section 
  about 
  60 
  feet 
  ; 
  length 
  of 
  do. 
  about 
  200 
  yards.) 
  

  

  6 
  x 
  

  

  l 
  l 
  

  

  1. 
  Gneiss. 
  2. 
  Gravel. 
  3. 
  Grey 
  Boulder-clay. 
  

  

  4. 
  Bed 
  Boulder-clay. 
  5. 
  Sandy 
  silt. 
  6. 
  Moraine 
  gravel. 
  

  

  1. 
  The 
  rock 
  at 
  the 
  base 
  is 
  a 
  coarse 
  granitic 
  gneiss 
  not 
  much 
  

   exposed, 
  and, 
  so 
  far 
  as 
  I 
  can 
  see, 
  exhibiting 
  no 
  clear 
  marks 
  of 
  glacia- 
  

   tion. 
  

  

  2. 
  The 
  lower 
  gravel 
  is 
  a 
  very 
  unusual 
  feature 
  in 
  this 
  quarter, 
  as 
  

   it 
  is 
  seldom 
  that 
  any 
  thing 
  is 
  found 
  between 
  the 
  rock 
  and 
  the 
  grey 
  

   Boulder-clay 
  above 
  it. 
  This 
  gravel 
  is 
  seen 
  only 
  at 
  the 
  south 
  end 
  of 
  

   the 
  section. 
  Where 
  it 
  commences 
  at 
  the 
  base 
  of 
  the 
  cliff 
  it 
  is 
  very 
  

   coarse, 
  with 
  a 
  few 
  large 
  boulders 
  of 
  granite 
  and 
  gneiss 
  from 
  3 
  to 
  

   5| 
  feet 
  in 
  diameter 
  ; 
  but 
  as 
  it 
  rises 
  and 
  thickens 
  in 
  the 
  bank 
  it 
  ceases 
  

   to 
  contain 
  any 
  large 
  boulders, 
  and 
  consists 
  of 
  waterworn 
  pebbly 
  

   gravel 
  and 
  sand, 
  the 
  stones 
  being 
  well 
  rounded 
  ; 
  in 
  mineral 
  quality, 
  

   they 
  consist 
  of 
  granite 
  and 
  gneiss, 
  similar 
  to 
  what 
  occur 
  in 
  the 
  grey 
  

   Boulder-clay 
  above. 
  This 
  lower 
  gravel 
  cannot 
  be 
  traced 
  for 
  any 
  great 
  

   length 
  beyond 
  the 
  section, 
  the 
  rocks 
  along 
  the 
  coast 
  to 
  the 
  south- 
  

   ward 
  being 
  covered 
  by 
  Boulder-clay. 
  I 
  could 
  see 
  no 
  trace 
  of 
  shells 
  

   in 
  this 
  gravel, 
  which 
  reaches 
  a 
  thickness 
  of 
  from 
  10 
  to 
  20 
  feet 
  at 
  its 
  

   southern 
  extremity. 
  

  

  3. 
  The 
  Boulder- 
  clay 
  which 
  forms 
  the 
  chief 
  mass 
  of 
  the 
  section 
  is 
  

   of 
  a 
  dull 
  grey 
  or 
  dun 
  colour, 
  is 
  very 
  compact, 
  firm 
  and 
  difficult 
  to 
  

   pierce, 
  stands 
  up 
  like 
  a 
  wall 
  with 
  a 
  perpendicular 
  or 
  even 
  over- 
  

   hanging 
  front 
  30 
  or 
  40 
  feet 
  high, 
  although 
  washed 
  at 
  the 
  base 
  by 
  

   the 
  surf 
  at 
  high 
  tide. 
  At 
  the 
  south 
  end 
  of 
  the 
  section 
  it 
  thius 
  off 
  

   considerably 
  and 
  rests 
  on 
  the 
  gravel 
  no. 
  2. 
  In 
  one 
  place, 
  near 
  the 
  

   middle 
  of 
  the 
  section, 
  it 
  rests 
  on 
  a 
  small 
  knob 
  of 
  gneiss 
  ; 
  but 
  further 
  

   north 
  its 
  bottom 
  is 
  not 
  exposed. 
  It 
  is 
  quite 
  unstratified, 
  very 
  tough 
  

   and 
  solid, 
  as 
  if 
  it 
  had 
  been 
  compressed 
  beneath 
  a 
  heavy 
  weight, 
  and 
  

   contains 
  no 
  broken 
  shells 
  or 
  organic 
  remains 
  of 
  any 
  kind, 
  so 
  far 
  as 
  

   I 
  could 
  perceive. 
  The 
  stones 
  in 
  it 
  are 
  of 
  granite 
  and 
  gneiss 
  of 
  

   several 
  varieties, 
  with 
  some 
  of 
  quartz-rock, 
  hornblende-schist, 
  

   felspar-porphyry, 
  and 
  greenstone, 
  the 
  last 
  not 
  common. 
  These 
  stones 
  

   have 
  their 
  angles 
  worn 
  off, 
  and 
  are 
  generally 
  of 
  small 
  sizes 
  ; 
  but 
  

   some 
  large 
  boulders 
  from 
  3 
  to 
  4 
  feet 
  in 
  diameter 
  occur 
  here 
  

   and 
  there 
  in 
  all 
  parts 
  of 
  the 
  mass 
  ; 
  and 
  still 
  larger 
  ones 
  are 
  seen 
  at 
  

   low 
  water 
  along 
  the 
  base 
  of 
  the 
  cliff, 
  which 
  have 
  no 
  doubt 
  been 
  

  

  