﻿1864.] 
  BELT 
  FORMATION 
  OP 
  LAKES. 
  463 
  

  

  7. 
  On 
  the 
  Formation 
  and 
  Preservation 
  of 
  Lakes 
  by 
  Ice 
  Action. 
  

   By 
  Thomas 
  Belt, 
  Esq. 
  

  

  [Communicated 
  by 
  Prof. 
  Eamsay, 
  F.E.S., 
  F.G.S.] 
  

   [Abstract.] 
  

  

  The 
  author 
  remarks 
  on 
  the 
  number 
  of 
  lakes, 
  great 
  and 
  small, 
  that 
  

   occur 
  in 
  Nova 
  Scotia, 
  either 
  in 
  connected 
  chains 
  or 
  isolated 
  on 
  the 
  

   tops 
  and 
  sides 
  of 
  the 
  hills. 
  It 
  is 
  a 
  common 
  feature 
  in 
  British 
  Ame- 
  

   rica, 
  increasing 
  as 
  we 
  proceed 
  northwards. 
  

  

  The 
  lakes 
  constituting 
  the 
  Shubenacadian 
  chain, 
  stretching 
  almost 
  

   across 
  the 
  province 
  of 
  Nova 
  Scotia, 
  are 
  found 
  by 
  the 
  author 
  to 
  be 
  in 
  

   true 
  rock-basins 
  of 
  hard 
  quartzites 
  and 
  metamorphosed 
  schists, 
  of 
  

   Lower 
  Silurian 
  age, 
  covered 
  irregularly 
  with 
  unstratified 
  Boulder- 
  

   clay. 
  The 
  surfaces 
  are 
  scratched, 
  grooved, 
  polished, 
  and 
  moutonnee, 
  

   and 
  bear 
  huge 
  transported 
  boulders. 
  

  

  The 
  direction 
  of 
  the 
  main 
  line 
  of 
  scratches 
  varies 
  from 
  N.N.E. 
  to 
  

   N.N.W., 
  and 
  is 
  coincident 
  with 
  the 
  major 
  axes 
  of 
  the 
  lakes. 
  The 
  

   Shubenacadian 
  lakes 
  commence 
  near 
  Dartmouth, 
  on 
  Halifax 
  Har- 
  

   bour, 
  and 
  stretch 
  in 
  an 
  irregular 
  northerly 
  direction 
  to 
  the 
  source 
  of 
  

   the 
  Shubenacadie 
  river, 
  a 
  distance 
  of 
  twenty-two 
  miles, 
  and, 
  with 
  the 
  

   river, 
  they 
  occupy 
  one 
  basin 
  of 
  a 
  great 
  depression 
  extending 
  from 
  

   Cobequid 
  Bay 
  to 
  Halifax 
  Harbour, 
  a 
  distance 
  of 
  fifty 
  miles. 
  The 
  

   largest 
  lake, 
  " 
  The 
  Grand,"' 
  is 
  eight 
  miles 
  long 
  ; 
  the 
  greatest 
  depth 
  is 
  

   74 
  feet 
  below 
  the 
  sea-level. 
  The 
  sea-coast 
  is 
  indented 
  by 
  long 
  and 
  

   narrow 
  fiords, 
  also 
  having 
  a 
  northerly 
  direction, 
  like 
  that 
  of 
  the 
  

   scratchings 
  and 
  of 
  the 
  chain 
  of 
  lakes. 
  

  

  The 
  glaciation 
  of 
  the 
  rocks 
  and 
  the 
  carriage 
  of 
  boulders 
  might 
  

   be 
  ascribed 
  to 
  the 
  agency 
  of 
  icebergs, 
  but 
  not 
  so 
  the 
  scooping-out 
  

   of 
  the 
  continuous 
  deep 
  channels 
  and 
  gorges 
  in 
  these 
  hard 
  rocks. 
  

   All 
  Nova 
  Scotia 
  is 
  grooved 
  and 
  furrowed 
  and 
  covered 
  by 
  masses 
  of 
  

   gravel. 
  The 
  configuration 
  of 
  the 
  country 
  is 
  explained 
  by 
  Agassiz 
  as 
  

   owing 
  to 
  a 
  vast 
  accumulation 
  of 
  continental 
  ice, 
  during 
  the 
  glacial 
  

   epoch, 
  moving 
  southwards 
  from 
  the 
  Arctic 
  regions, 
  and 
  scooping 
  out 
  

   the 
  larger 
  valleys 
  and 
  deep 
  fiords. 
  During 
  its 
  retrogression, 
  the 
  ice 
  

   wasted 
  into 
  separate 
  glaciers 
  in 
  the 
  principal 
  valleys, 
  and 
  there 
  left 
  

   terminal 
  moraines 
  in 
  their 
  courses, 
  and 
  heaps 
  of 
  gravel, 
  &c, 
  on 
  their 
  

   flanks. 
  

  

  It 
  may 
  be 
  admitted 
  that 
  such 
  lakes 
  as 
  are 
  formed 
  by 
  damming 
  up 
  

   channels 
  by 
  heaps 
  of 
  gravel 
  and 
  clay 
  may 
  have 
  been 
  caused 
  by 
  

   glaciers 
  leaving 
  terminal 
  moraines 
  in 
  their 
  retreat, 
  but 
  the 
  produc- 
  

   tion 
  of 
  deep 
  rock-basins 
  is 
  not 
  thus 
  to 
  be 
  accounted 
  for. 
  

  

  Prof. 
  Ramsay, 
  in 
  1859, 
  showed 
  that 
  there 
  was 
  an 
  intimate 
  con- 
  

   nexion 
  between 
  mountain 
  lakes 
  and 
  glaciers, 
  and 
  that 
  the 
  rock- 
  

   basins 
  have 
  been 
  ground 
  or 
  scooped 
  out 
  by 
  ice; 
  and 
  in 
  1862 
  he 
  

   applied 
  his 
  theory 
  to 
  the 
  production 
  of 
  the 
  lakes 
  of 
  Switzerland 
  and 
  

   North 
  America, 
  contending 
  that 
  there 
  is 
  such 
  a 
  gradation 
  of 
  size 
  

   from 
  the 
  least 
  to 
  the 
  greatest 
  that 
  the 
  theory 
  is 
  applicable 
  to 
  all. 
  

  

  Sir 
  C. 
  Lyell 
  urges 
  that 
  though 
  the 
  passage 
  of 
  ice 
  over 
  the 
  surface 
  

   for 
  ages 
  would 
  doubtless 
  produce 
  depression 
  where 
  the 
  hardness 
  of 
  

   the 
  rocks 
  beneath 
  was 
  not 
  uniform, 
  yet 
  a 
  depth 
  would 
  soon 
  be 
  

  

  2k2 
  

  

  