﻿140 
  MR. 
  A. 
  STRAHAN 
  ON 
  GLACIAL 
  PHENOMENA 
  OF 
  [May 
  1 
  897,, 
  

  

  consists 
  of 
  irregularly-bedded 
  sandstones 
  with 
  grey 
  and 
  purplish 
  

   shales. 
  The 
  sandstones 
  occur 
  in 
  the 
  most 
  irregular 
  manner 
  an& 
  

   wedge 
  in 
  so 
  suddenly 
  as 
  almost 
  to 
  resemble 
  included 
  masses 
  ; 
  they 
  

   contain 
  also 
  fragments 
  of 
  shale 
  more 
  or 
  less 
  rolled, 
  and 
  in 
  this 
  and 
  

   other 
  respects 
  indicate 
  that 
  deposition 
  alternated 
  with 
  erosion 
  under 
  

   the 
  influence 
  of 
  variable 
  currents. 
  The 
  rather 
  bolder 
  cliff 
  on 
  the 
  

   southern 
  side 
  of 
  Yadso 
  Island 
  presents 
  crags 
  of 
  grey 
  quartz-grit 
  

   separated 
  by 
  upwards 
  of 
  20 
  feet 
  of 
  fine 
  red 
  sandstone, 
  current- 
  

   bedded 
  in 
  thin 
  laminae. 
  I 
  saw 
  also 
  on 
  the 
  hillsides 
  boulders 
  which 
  

   I 
  believe 
  to 
  have 
  been 
  derived 
  from 
  the 
  Gaisa 
  rocks, 
  in 
  which 
  frag- 
  

   ments 
  of 
  dolomite 
  were 
  abundant. 
  

  

  •In 
  all 
  these 
  respects 
  the 
  Gaisa 
  Beds 
  present 
  only 
  such 
  features- 
  

   as 
  are 
  common 
  to 
  rocks 
  of 
  the 
  type 
  of 
  the 
  Wealden, 
  Trias, 
  Coal 
  

   Measures, 
  or 
  Old 
  Eed 
  Sandstone, 
  and 
  give 
  no 
  hint 
  of 
  the 
  action 
  

   of 
  ice. 
  But 
  on 
  visiting 
  the 
  section 
  near 
  Bigganjargga, 
  1 
  referred 
  

   to 
  by 
  Dr. 
  Eeusch, 
  I 
  found 
  a 
  deposit 
  of 
  which 
  I 
  have 
  seen 
  no- 
  

   counterpart 
  in 
  any 
  of 
  those 
  formations. 
  The 
  cliff 
  there 
  rises 
  from 
  

   the 
  shore 
  in 
  a 
  succession 
  of 
  rock-ledges, 
  the 
  strata 
  being 
  nearly 
  

   horizontal 
  and 
  free 
  from 
  surface-deposits. 
  In 
  the 
  lowest 
  ledge, 
  

   just 
  above 
  high-tide 
  mark, 
  a 
  lenticular 
  mass 
  of 
  darker 
  rock 
  inter- 
  

   calated 
  between 
  the 
  ledges 
  of 
  sandstone 
  at 
  once 
  arrests 
  the 
  atten- 
  

   tion, 
  even 
  as 
  seen 
  from 
  the 
  deck 
  of 
  a 
  steamer 
  (PI. 
  VIII). 
  The 
  

   mass 
  wedges 
  in 
  abruptly, 
  and 
  at 
  a 
  distance 
  of 
  about 
  4 
  yards 
  from 
  

   the 
  point 
  of 
  its 
  first 
  appearance 
  attains 
  a 
  thickness 
  of 
  8 
  feet. 
  

   Thence 
  it 
  runs 
  for 
  about 
  70 
  yards 
  at 
  the 
  foot 
  of 
  the 
  cliff, 
  until 
  

   the 
  gentle 
  dip 
  carries 
  it 
  beneath 
  the 
  sea, 
  the 
  thickness 
  nowhere 
  

   exceeding 
  about 
  10 
  feet. 
  Its 
  base 
  is 
  remarkably 
  straight, 
  for 
  a 
  

   reason 
  given 
  hereafter 
  ; 
  but 
  its 
  upper 
  surface 
  undulates 
  as 
  the 
  

   thickness 
  of 
  the 
  mass 
  varies, 
  and 
  on 
  these 
  undulations 
  the 
  overlying 
  

   sandstones 
  have 
  been 
  tranquilly 
  deposited 
  in 
  such 
  a 
  way 
  as 
  to 
  level- 
  

   up 
  the 
  irregularities, 
  some 
  of 
  the 
  beds 
  thinning 
  away 
  against 
  the 
  

   sloping 
  sides 
  of 
  the 
  mass 
  (PI. 
  IX), 
  while 
  others 
  overtop 
  it 
  and 
  

   extend 
  continuously 
  across 
  it. 
  

  

  Having 
  been 
  deposited 
  on 
  a 
  sloping 
  surface, 
  these 
  strata 
  vary 
  in 
  

   thickness 
  and 
  are 
  slightly 
  inclined, 
  but 
  in 
  the 
  overlying 
  sediments 
  

   all 
  such 
  irregularities 
  of 
  deposition 
  gradually 
  disappear, 
  and 
  a 
  few 
  

   feet 
  up 
  in 
  the 
  cliff 
  the 
  bedding 
  runs 
  evenly 
  and 
  uninterruptedly 
  over 
  

   the 
  site 
  of 
  the 
  buried 
  lenticle. 
  For 
  an 
  inch 
  or 
  two 
  at 
  their 
  base 
  

   the 
  sandstones 
  in 
  contact 
  with 
  the 
  buried 
  mass 
  contain 
  material 
  

   washed 
  up 
  from 
  its 
  surface. 
  

  

  The 
  mass 
  itself 
  is 
  a 
  boulder-rock 
  quite 
  unlike 
  any 
  of 
  the 
  Gaisa 
  

   sandstones 
  or 
  conglomerates 
  which 
  I 
  saw 
  elsewhere. 
  It 
  is 
  referred 
  

   to 
  by 
  Dr. 
  Eeusch 
  as 
  a 
  conglomerate, 
  but 
  from 
  the 
  fact 
  of 
  its 
  being 
  

   neither 
  stratified 
  nor 
  waterworn 
  I 
  prefer 
  to 
  avoid 
  the 
  use 
  of 
  that 
  

   term. 
  It 
  may 
  be 
  described 
  as 
  a 
  dark-bluish 
  or 
  ashy-grey 
  friable 
  

   rock, 
  composed 
  of 
  a 
  heterogeneous 
  mixture 
  of 
  grit, 
  sand, 
  and 
  clay 
  

  

  1 
  The 
  section 
  is 
  exposed 
  about 
  2 
  miles 
  north-east 
  of 
  the 
  two 
  or 
  three 
  Lapp 
  

   huts 
  known 
  by 
  that 
  name, 
  and 
  about 
  a 
  mile 
  west 
  of 
  the 
  Island 
  of 
  Suolo- 
  

   shown 
  on 
  the 
  map 
  (p. 
  138). 
  

  

  