ANNIVERSARY  ADDRESS  OF  THE  PRESIDENT. 
81 
7ol.  49.] 
it  is  occasionally  quite  free  from  clay,  consisting  of  gravel  and  sand 
so  disturbed  that  all  traces  of  original  stratification,  if  ever  they 
existed,  have  been  destroyed.  All  the  Boulder-clays  and  gravels 
from  the  early  Pennine  down  to  the  4  Interglacial  River-gravel 9 
have  been  crushed  at  the  surface,  or  even  partially  converted  into 
newer  Boulder-clay. 
Crossing  the  Cheshire  plain,  we  must  now  follow  Messrs.  Strahan, 
Hughes,  and  Hicks  in  their  descriptions  of  some  of  the  Pleistocene 
phenomena  of  North  "Wales  and  its  borders.  The  first-named 
Author  tells  us  that  in  the  neighbourhood  of  Liverpool  the  materials 
of  the  Drift  have  travelled  from  the  N.W.,  and  that  the  edges  of  the 
strata  have  in  many  cases  been  bent  back  also  from  the  N.W.,  the 
same  agent  which  distributed  the  Boulder-clay  having  presumably 
striated  the  rock-surface.  On  the  Welsh  border  the  striations  are 
said  to  show  a  general  parallelism,  as  though  the  direction  of  the 
movement  of  the  Drift  was  from  the  W.S.W.,  and  the  transportation 
of  much  of  this  Drift  has  taken  place  across  the  lines  of  the  prin¬ 
cipal  hill-ranges  and  valleys.  It  would  seem  that  in  a  valley  such 
as  that  of  the  Dee,  which  is  in  part  conformable  to  the  mean 
direction  of  the  movement,  this  is  less  evident  than  in  the  valley  of 
the  Clwyd,  which  seems  to  have  been  crossed  almost  at  right  angles 
to  its  axis.  The  line  of  demarcation  of  these  two  partly  opposing 
Drifts  is  shown  on  a  map. 
When  Mr.  Strahan  discussed  the  merits  of  the  rival  hypotheses, 
firstly  of  two  ice-sheets  moving  in  different  directions,  and  secondly 
the  agency  of  floating  ice,  he  was  (at  that  time)  in  favour  of  the  latter 
view,  concluding  that  the  marine  drifts  and  their  striations  were 
produced  by  floating  ice  during  a  period  of  submergence.  Amongst 
his  reasons  for  thus  deciding,  he  pointed  out  that  the  rock-surface 
is  not  4  moutonnee  ’  on  a  large  scale,  and  that  the  striae  and 
terminal  curvature  are  far  from  being  universal ;  and  he  further 
observes  that  the  marine  origin  of  the  drifts  is  indicated  by  their 
well-marked  stratification,  as  a  whole,  and  by  the  occurrence  through¬ 
out  all  the  beds  of  marine  shells.  Some  of  these  arguments  may  be 
good,  but  it  has  always  seemed  to  me  that  anything  approaching  to 
parallelism  in  a  system  of  striations  could  only  be  effected  by  an 
agent  moving  more  or  less  in  one  direction,  which  is  hardly  what 
we  should  expect  of  floating  ice,  subject  to  the  irregularities  of 
winds  and  currents,  even  supposing  that  floating  ice  is  capable  of 
rock-grooving  on  a  large  scale.  I  venture  to  make  these  comments, 
because  the  views  then  advocated  by  Mr.  Strahan  seem  to  represent 
