Yol.  49.]  ANNIVERSARY  ADDRESS  OE  THE  PRESIDENT.  87 
accumulate  on  these  low  watersheds,  and  thus  helped  to  supply  the 
impetus  or  vis-a-tergo  which  the  actually  existing  watersheds  seem 
barely  sufficient  to  explain. 
According  to  this  hypothesis,  then,  the  ice  of  Ireland,  Scotland, 
and  England  in  combination  essayed  to  force  a  portion  of  the  bed  of 
the  Irish  Sea  up  the  flanks  of  the  Welsh  highlands,  and  this  attack 
was  to  a  certain  extent  parried  by  the  native  ice-streams,  since  it 
has  been  remarked  that  the  shell-bearing  High-level  Glacial  Sands 
have  as  yet  only  been  found  upon  the  outskirts  of  the  mountainous 
areas,  such  as  Moel  Tryfaen  on  the  west  and  Gloppa  on  the  east. 
In  its  progress  southwards  there  were  only  two  channels  for  the 
escape  and  melting  of  the  ice,  viz.  St.  George’s  Channel,  and  the 
depression  represented  by  the  plain  of  Cheshire  and  Shropshire.  If 
this  be  the  true  explanation,  it  would  seem  that  this  plain  must  have 
been  filled  with  ice  for  some  distance  up  the  western  flank  of  the 
Pennine  Chain,  since  the  deposits  above  Macclesfield  in  all  probability 
originated  in  a  manner  similar  to  those  at  Gloppa. 
East  Yorkshire. — The  history  of  the  drifts  in  this  part  of  England, 
though  sufficiently  obscure,  does  not  make  quite  so  large  a  demand 
upon  our  faith,  mainly  perhaps  because  the  heights  traversed  by 
the  presumed  glacier  of  the  North  Sea  are  not  so  lofty  as  in  the 
cases  just  quoted  from  the  west  side  of  our  island.  Mr.  Lamplugh, 
after  pointing  out  the  importance  of  the  Elamborough  promontory 
as  a  locality  where  the  connexion  between  the  drift  of  the  hills  and 
that  of  the  plains  may  be  traced,  states  that  he  finds  himself  com¬ 
pelled  to  dissent  from  the  views  expressed  a  quarter  of  a  century  ago 
in  the  Quarterly  Journal  by  Messrs.  Wood  and  Pome.  In  opposition 
to  their  hitherto  accepted  correlation  he  concludes  that  the  triple 
division  of  Hessle  Clay,  Purple  Clay,  and  Basement  Clay  may  be 
recognized  to  a  certain  extent  farther  north  than  Holderness.  More¬ 
over,  he  declares  that  he  no  longer  has  faith  in  the  occurrence  of  the 
so-called  4  Interglacial  Periods.’  He  claims  that  in  East  Yorkshire 
the  glacial  deposits  attain  their  greatest  development  near  the  coast¬ 
line,  and  that  inland  from  Elamborough  they  thin  away  so  rapidly 
that  the  Chalk  often  carries  nothing  more  than  a  scanty  covering 
of  clay  within  a  few  hundred  yards  of  the  edge  of  the  cliff. 
Into  the  details  of  this  remarkable  paper  we  cannot  of  course  enter, 
but  if  we  accept  his  main  conclusions  as  deduced  from  a  study  of 
the  sections,  the  following  are  some  of  the  results  at  which  he 
arrives.  These  results  constitute  a  sort  of  epitome  of  the  history  of 
Pleistocene  time  within  the  district. 
Starting  with  the  lowest  beds,  Mr.  Lamplugh  observes  that  we 
