﻿Glacial 
  Geology 
  of 
  Spitsbergen. 
  541 
  

  

  February 
  2ud. 
  — 
  Dr. 
  Henry 
  Hicks, 
  F.R.S., 
  President, 
  

   in 
  the 
  Chair. 
  

   The 
  following 
  communications 
  were 
  read 
  : 
  — 
  

   1. 
  ' 
  Contributions 
  to 
  the 
  Glacial 
  Geology 
  of 
  Spitsbergen.' 
  By 
  

   E. 
  J. 
  Garwood, 
  Esq., 
  M.A., 
  F.G.S., 
  and 
  Dr. 
  J. 
  W. 
  Gregory, 
  

   F.G.S. 
  

  

  The 
  extent 
  of 
  glaciation 
  of 
  Spitsbergen 
  has 
  been 
  exaggerated, 
  

   for 
  there 
  is 
  no 
  immense 
  ice-plateau, 
  but 
  normal 
  glaciers 
  with 
  some 
  

   inland 
  sheets 
  and 
  Piedmont 
  glaciers. 
  These 
  differ 
  from 
  Alpine 
  

   glaciers, 
  as 
  they 
  are 
  not 
  always 
  formed 
  from 
  snow-fields 
  at 
  the 
  head, 
  

   and 
  though 
  some 
  of 
  the 
  glaciers 
  (as 
  the 
  Baldhead 
  Glacier) 
  have 
  

   tapering 
  snouts 
  in 
  front, 
  mo3t 
  have 
  vertical 
  cliffs. 
  Chamberlin's 
  

   explanation 
  that 
  the 
  latter 
  are 
  due 
  to 
  the 
  low 
  angle 
  of 
  the 
  sun 
  is 
  

   insufficient, 
  and 
  they 
  seem 
  to 
  be 
  caused 
  by 
  the 
  advance 
  of 
  the 
  

   ice 
  by 
  a 
  rapid 
  forward 
  movement 
  of 
  its 
  upper 
  layers. 
  The 
  ice 
  of 
  

   these 
  upper 
  layers 
  falls 
  off 
  and 
  forms 
  talus 
  in 
  front, 
  over 
  which 
  the 
  

   glacier 
  advances, 
  carrying 
  detritus 
  uphill 
  with 
  it, 
  and 
  producing 
  

   a 
  series 
  of 
  thrusts. 
  The 
  Booming 
  Glacier 
  illustrates 
  cases 
  of 
  

   erratics 
  carried 
  in 
  different 
  directions 
  by 
  the 
  same 
  mass 
  of 
  ice. 
  

  

  The 
  deposits 
  of 
  the 
  Spitsbergen 
  glaciers 
  are 
  of 
  four 
  types 
  : 
  — 
  

   (1) 
  moraines 
  of 
  Swiss 
  type 
  ; 
  (2) 
  those 
  formed 
  mainly 
  of 
  intraglacial 
  

   material 
  ; 
  (3) 
  those 
  formed 
  of 
  redeposited 
  beach-material 
  ; 
  (4) 
  de- 
  

   posits 
  of 
  glacial 
  rivers, 
  and 
  re-assorted 
  drifts. 
  The 
  materials 
  of 
  the 
  

   second 
  are 
  subangular 
  and 
  rounded 
  ; 
  scratched 
  and 
  polished 
  pebbles 
  

   and 
  boulders 
  are 
  abundant, 
  and 
  the 
  fine-grained 
  matrix, 
  which 
  is 
  

   frequently 
  argillaceous, 
  is 
  often 
  well-laminated 
  and 
  false-bedded. 
  

   Some 
  of 
  these 
  drifts 
  are 
  stratified, 
  others 
  unstratified, 
  and 
  contorted 
  

   drifts 
  occur. 
  This 
  type 
  of 
  moraine 
  is 
  remarkably 
  like 
  some 
  British 
  

   Boulder 
  Clay. 
  The 
  third 
  class 
  is 
  sometimes 
  formed 
  by 
  land-ice, 
  at 
  

   other 
  times 
  beneath 
  the 
  sea 
  ; 
  the 
  latter 
  shows 
  stratification. 
  The 
  

   superglacial 
  and 
  intraglacial 
  streams, 
  so 
  far 
  as 
  seen, 
  were 
  usually 
  

   clear 
  of 
  drift. 
  Under 
  the 
  fourth 
  head 
  an 
  esker 
  in 
  a 
  tributary 
  of 
  

   the 
  Sassendal 
  is 
  described. 
  

  

  The 
  direct 
  geological 
  action 
  of 
  the 
  marine 
  ice 
  is 
  of 
  four 
  kinds 
  : 
  — 
  

   transport 
  of 
  material, 
  contortion 
  of 
  shore- 
  deposits, 
  formation 
  of 
  

   small 
  ridges 
  of 
  boulder-terraces 
  above 
  sea-level, 
  and 
  striation, 
  

   rounding, 
  and 
  furrowing 
  of 
  rocks 
  along 
  the 
  sea-shore. 
  

  

  Traces 
  of 
  former 
  glaciation 
  are 
  described 
  in 
  the 
  case 
  of 
  the 
  

   Hecla 
  Hook 
  beds, 
  and 
  of 
  certain 
  beds 
  of 
  late 
  Mesozoic 
  or 
  early 
  

   Cainozoic 
  age 
  in 
  Bunting 
  Bluff. 
  

  

  Under 
  the 
  head 
  of 
  general 
  conclusions 
  the 
  authors 
  state 
  that 
  

   they 
  have 
  discovered 
  no 
  certain 
  test 
  to 
  distinguish 
  between 
  the 
  

   action 
  of 
  land-ice 
  and 
  marine 
  ice 
  ; 
  that 
  there 
  is 
  no 
  evidence 
  to 
  

   prove 
  that 
  land-ice 
  can 
  advance 
  far 
  across 
  the 
  sea 
  ; 
  and 
  that 
  

   there 
  is 
  evidence, 
  which 
  they 
  regard 
  as 
  conclusive, 
  of 
  the 
  uplift 
  of 
  

   materials 
  by 
  land-ice. 
  They 
  note 
  that 
  the 
  mechanical 
  processes 
  

   connected 
  with 
  the 
  advance 
  of 
  the 
  glaciers 
  are 
  of 
  three 
  kinds. 
  All 
  

   the 
  material 
  seen 
  transported 
  by 
  the 
  glaciers 
  was 
  superglacial 
  or 
  

   intraglacial, 
  and 
  not 
  subglacial. 
  Some 
  striation 
  of 
  intraglacial 
  

   material 
  is 
  caused 
  by 
  differential 
  movement 
  of 
  different 
  layers 
  of 
  ice. 
  

  

  