﻿246 
  PEOCEEDI]S 
  T 
  GS 
  OP 
  THE 
  GEOLOGICAL 
  SOCIETY. 
  

  

  8. 
  " 
  On 
  the 
  Cause 
  of 
  the 
  Depression 
  and 
  Re-elevation 
  of 
  the 
  

   Land 
  during 
  the 
  Glacial 
  Period." 
  By 
  T. 
  E. 
  Jamieson, 
  Esq., 
  E.G.S. 
  

  

  [Abstract.] 
  

  

  The 
  author 
  commenced 
  by 
  noticing 
  the 
  theory 
  advanced 
  by 
  Adhe- 
  

   mar 
  and 
  Croll, 
  according 
  to 
  which 
  the 
  submergence 
  was 
  due 
  to 
  the 
  

   effect 
  of 
  a 
  polar 
  ice-cap 
  causing 
  a 
  displacement 
  of 
  the 
  earth's 
  centre 
  

   of 
  gravity 
  and 
  thereby 
  drawing 
  the 
  ocean 
  towards 
  the 
  ice-covered 
  

   pole, 
  and 
  proceeded 
  to 
  show 
  that 
  this 
  theory 
  is 
  opposed 
  to 
  the 
  geolo- 
  

   gical 
  evidence, 
  according 
  to 
  which 
  the 
  amount 
  of 
  submergence 
  has 
  

   been 
  unequal 
  in 
  adjacent 
  areas 
  and 
  along 
  the 
  same 
  parallels 
  of 
  

   latitude, 
  showing 
  that 
  the 
  movement 
  has 
  been 
  in 
  the 
  land, 
  and 
  not 
  

   in 
  the 
  sea. 
  The 
  facts 
  of 
  submergence 
  also 
  prove 
  that 
  no 
  such 
  cap 
  

   of 
  ice 
  could 
  have 
  existed 
  at 
  the 
  time 
  in 
  the 
  northern 
  regions. 
  

   Sundry 
  other 
  objections 
  were 
  also 
  pointed 
  out. 
  The 
  author 
  then 
  

   went 
  on 
  to 
  state 
  his 
  own 
  hypothesis, 
  which 
  is 
  to 
  the 
  effect 
  that 
  the 
  

   depression 
  of 
  the 
  land 
  was 
  caused 
  by 
  the 
  weight 
  of 
  ice 
  laid 
  upon 
  it, 
  

   and 
  the 
  re-elevation 
  by 
  the 
  disappearance 
  of 
  the 
  ice. 
  The 
  amount 
  

   of 
  depression 
  would 
  depend 
  partly 
  on 
  the 
  weight 
  of 
  ice 
  and 
  partly 
  

   on 
  the 
  elasticity 
  or 
  yielding 
  nature 
  of 
  the 
  ground 
  beneath 
  it. 
  He 
  

   then 
  proceeded 
  to 
  consider 
  what 
  was 
  the 
  weight 
  of 
  ice 
  that 
  probably 
  

   existed, 
  and 
  referred 
  to 
  the 
  elastic 
  and 
  flexible 
  nature 
  of 
  the 
  earth's 
  

   crust, 
  as 
  evinced 
  by 
  earthquakes 
  &c. 
  

  

  He 
  further 
  considered 
  the 
  relation 
  of 
  time 
  to 
  pressure, 
  and 
  touched 
  

   upon 
  the 
  probable 
  rate 
  of 
  subsidence, 
  which 
  he 
  supposes 
  to 
  have 
  

   been 
  very 
  slow 
  and 
  gradual. 
  The 
  recovery 
  of 
  level, 
  he 
  thinks, 
  would 
  

   also 
  be 
  very 
  gradual, 
  and 
  probably, 
  in 
  most 
  cases, 
  not 
  complete. 
  

  

  He 
  next 
  proceeded 
  to 
  show 
  how 
  his 
  hypothesis 
  is 
  borne 
  out 
  by 
  an 
  

   appeal 
  to 
  geological 
  evidence 
  in 
  various 
  countries, 
  taking 
  England, 
  

   Ireland, 
  North 
  America, 
  and 
  Greenland 
  as 
  examples. 
  He 
  further 
  

   pointed 
  out 
  its 
  application 
  to 
  the 
  facts 
  connected 
  with 
  the 
  loess 
  beds, 
  

   Ejord 
  latitudes, 
  and 
  lake-basins, 
  and 
  concluded 
  with 
  some 
  observa- 
  

   tions 
  on 
  the 
  remarkable 
  connexion 
  between 
  glaciation 
  and 
  submer- 
  

   gence 
  in 
  all 
  countries. 
  

  

  The 
  following 
  specimens 
  were 
  exhibited 
  : 
  — 
  

  

  Remains 
  of 
  a 
  small 
  species 
  of 
  Ifoa 
  (Dinomis 
  didulus, 
  Owen, 
  sp. 
  n.) 
  

   from 
  New 
  Zealand, 
  showing 
  portions 
  of 
  the 
  skin 
  and 
  feathers, 
  exhi- 
  

   bited 
  by 
  Dr. 
  H. 
  \Y00dward. 
  

  

  Specimens 
  of 
  Sphenospondylus 
  and 
  Thecospondi/hu; 
  Homeri, 
  exhi- 
  

   bited 
  by 
  Prof. 
  H. 
  G. 
  Seeley, 
  in 
  illustration 
  of 
  his 
  papers. 
  

  

  Specimens 
  exhibited 
  by 
  W. 
  H. 
  Twelvetrees, 
  Esq., 
  and 
  E. 
  Wil- 
  

   son, 
  Esq., 
  in 
  illustration 
  of 
  their 
  papers. 
  

  

  