﻿150 
  

  

  MR. 
  A. 
  STRAHAN 
  ON 
  THE 
  RAISED 
  REACHES 
  AND 
  [May 
  1897, 
  

  

  glacial 
  striae, 
  led 
  me 
  at 
  first 
  sight 
  to 
  believe 
  it 
  to 
  be 
  a 
  till, 
  an 
  opinion 
  

   which 
  I 
  had 
  occasion 
  to 
  change. 
  

  

  At 
  Bodo 
  there 
  occurs 
  a 
  somewhat 
  similar 
  deposit. 
  It 
  forms 
  a 
  

   terrace 
  about 
  70 
  to 
  80 
  feet 
  high, 
  on 
  which 
  the 
  town 
  is 
  built, 
  and 
  

   consists 
  of 
  a 
  bluish 
  sandy 
  clay, 
  with 
  many 
  included 
  stones 
  and 
  

   shells 
  of 
  Leda 
  (Yoldia) 
  arctica 
  in 
  the 
  position 
  of 
  life 
  ; 
  it 
  rests 
  on 
  a 
  

   rock-surface 
  which 
  is 
  conspicuously 
  moutonnee, 
  but 
  from 
  which 
  the 
  

   striae 
  have 
  been 
  obliterated. 
  Upon 
  it, 
  at 
  a 
  height 
  of 
  70 
  to 
  80 
  feet 
  

   above 
  the 
  sea, 
  there 
  lies 
  a 
  shell-marl 
  containing, 
  among 
  others, 
  

   he 
  following 
  shells 
  l 
  : 
  — 
  

  

  Mya 
  truncata, 
  very 
  abundant, 
  

  

  with 
  the 
  valves 
  united. 
  

   Purpura 
  lapillus. 
  

   Trochus, 
  

  

  Littorina 
  littorea. 
  

  

  Littorina 
  obtusata. 
  

   Hydrobia 
  ulvcs 
  (?). 
  

   Lacuna 
  crassior. 
  

   Broken 
  nullipore 
  and 
  rolled 
  

   echinoderin-spines. 
  

  

  At 
  Tromso 
  I 
  noticed 
  a 
  similar 
  blue 
  clay, 
  and 
  resting 
  upon 
  it, 
  at 
  a 
  

   height 
  of 
  about 
  10 
  feet 
  above 
  the 
  sea, 
  a 
  shell-marl 
  from 
  1 
  to 
  3 
  feet 
  

   thick, 
  in 
  which 
  the 
  following 
  occurred 
  : 
  — 
  

  

  Pecten 
  islandicus. 
  

   Mytilus 
  edulis. 
  

   Mya 
  truncata. 
  

   Saxicava 
  rugosa. 
  

   Cardium 
  edtde. 
  

   Astarte 
  borealis. 
  

   sulcata. 
  

  

  Astarte 
  compressa. 
  

   Tellina 
  calcarea. 
  

   Littorina 
  littorea. 
  

   Tectum. 
  

  

  Balanus 
  porcatus. 
  

   And 
  much 
  nullipore. 
  

  

  On 
  the 
  mainland 
  opposite 
  Tromso 
  the 
  clay 
  is 
  worked 
  for 
  brick- 
  

   making, 
  and 
  is 
  described 
  by 
  Colonel 
  Feilden 
  as 
  ' 
  a 
  homogeneous 
  

   •mass 
  of 
  blue 
  clay 
  with 
  boulders 
  and 
  stones 
  interspersed 
  throughout. 
  

   There 
  is 
  not 
  a 
  trace 
  of 
  bedding 
  throughout 
  the 
  mass 
  . 
  . 
  . 
  the 
  clay 
  

   contains 
  ice-scratched 
  stones, 
  and 
  mollusca 
  are 
  abundant 
  throughout 
  

   the 
  bed 
  ; 
  examples 
  of 
  Cyprina 
  islandica 
  and 
  Pecten 
  islandicus, 
  

   partially 
  retaining 
  their 
  colour, 
  are 
  common, 
  likewise 
  stones 
  to 
  

   which 
  the 
  bases 
  of 
  a 
  Balanus 
  are 
  attached.' 
  2 
  In 
  all 
  these 
  cases 
  

   mud 
  is 
  the 
  material 
  forming 
  the 
  bottom 
  of 
  the 
  fiord. 
  

  

  My 
  reasons 
  for 
  not 
  applying 
  the 
  term 
  ' 
  till 
  ' 
  to 
  this 
  deposit 
  

   are 
  briefly 
  as 
  follows 
  : 
  — 
  Till, 
  or 
  the 
  almost 
  synonymous 
  term 
  

   Boulder 
  Clay, 
  which 
  is 
  used 
  for 
  this 
  clay 
  by 
  Col. 
  Feilden, 
  always 
  

   contains 
  grit 
  and 
  sand, 
  and 
  generally 
  in 
  larger 
  proportions 
  than 
  

   appear 
  at 
  first 
  sight. 
  When 
  the 
  proportion 
  of 
  clay 
  is 
  high, 
  it 
  is 
  

   always 
  because 
  argillaceous 
  formations 
  have 
  formed 
  the 
  source 
  of 
  

   supply, 
  but 
  even 
  then 
  it 
  is 
  a 
  heterogeneous 
  mixture 
  of 
  materials 
  

   of 
  all 
  degrees 
  of 
  coarseness, 
  bearing 
  internal 
  evidence 
  of 
  having 
  been 
  

   churned 
  up, 
  but 
  not 
  sorted 
  under 
  water. 
  The 
  fiord-clay, 
  on 
  the 
  

   other 
  hand, 
  is 
  a 
  homogeneous 
  clay 
  or 
  fine 
  silty 
  sand, 
  such 
  as 
  could 
  

   hardly 
  have 
  been 
  accumulated 
  except 
  by 
  the 
  sorting 
  action 
  of 
  

   water. 
  It 
  contains 
  delicate 
  mollusca, 
  nearly 
  all 
  in 
  a 
  perfect 
  con- 
  

   dition, 
  with 
  the 
  valves 
  united; 
  while, 
  lastly, 
  it 
  is 
  not 
  such 
  a 
  material 
  

  

  1 
  These 
  and 
  the 
  other 
  shells 
  were 
  identified 
  for 
  me 
  by 
  Mr. 
  Clement 
  Eeid. 
  

   The 
  deposit 
  was 
  noticed 
  so 
  long 
  ago 
  as 
  1850 
  by 
  Chambers, 
  ' 
  Tracings 
  of 
  the 
  

   JSbrth 
  of 
  Europe,' 
  p. 
  134. 
  

  

  2 
  Quart. 
  Journ. 
  Geol. 
  Soc. 
  vol. 
  lii. 
  (1896) 
  p. 
  723. 
  

  

  