38 
PROCEEDINGS  OE  THE  GEOLOGICAL  SOCIETY. 
[May  1893, 
are  met  at  the  very  outset  by  a  question  of  the  highest  importance. 
This  refers  to  the  so-called  4  inffa-Glacial 5  Beds  of  Sewerby  and 
Speeton.  At  the  former  place  occurs  a  buried  cliff  of  Chalk,  with 
fossiliferous  beds  (containing  Mammalia  and  land  and  marine 
Mollusca)  banked  against  it,  the  whole  being  surmounted  by  a  more 
or  less  complete  series  of  the  Glacial  Beds.  Are  these  beds,  which 
underlie  the  Basement  Boulder-clay,  to  be  considered  as  older  than 
the  Glacial  Period,  or  are  they  of  inter-Glacial  age,  formed  during 
an  interval  between  the  periods  of  glaciation  ?  The  fauna  is  rather 
meagre,  though  the  Elephant- remains  hitherto  found  at  Sewerby 
have  been  determined  as  E.  antiquus.  One  of  the  most  curious 
features  in  connexion  with  this  old  beach  at  Sewerby  relates  to  the 
pebbles  it  contains.  There  is  no  trace  of  Mountain  Limestone  or 
other  recognizable  Carboniferous  rock,  and  the  inference  seems  fair 
that  no  glaciers  from  the  Pennine  Chain  reached  the  east  coast  at 
this  period.  Though  there  can  be  little  doubt  of  the  ice-borne 
character  of  these  pebbles,  it  is  not  clear  whether  they  have  been 
carried  to  this  beach  by  floating  ice,  or  have  been  derived  at  second 
hand  from  an  older  glacial  deposit.  The  Author  is  inclined  to  adopt 
the  former  view,  and  generally  contests,  throughout  the  whole  of  his 
paper,  the  notion  of  an  inter-Glacial  period.  As  regards  the  corre¬ 
lation  of  his  ‘  infra-Glacial  ’  beds,  while  admitting  that  they  may 
not  be  strictly  pre-Glacial,  since  the  district  was  not  likely  to  be 
invaded  by  land-ice  until  long  after  the  commencement  of  glacial 
conditions,  he  thinks  they  contain  the  record  of  a  period  anterior 
to  the  first  glaciation  of  the  east  coast,  and  may  be  as  old  as  the 
Leda  myalis-bed  in  Norfolk. 
Owing  to  the  physical  character  of  the  district  and  its  distance 
from  lofty  mountains,  it  may  be  inferred  that  a  long  interval  of 
severe  climate  ensued  before  anything  like  an  ice-sheet  reached 
this  area.  This  period  would  naturally  be  indicated  on  the  Wolds 
by  subaerial  deposits  of  the  nature  of  disintegrated  rock,  which 
would  be  swept  down  into  the  hollows,  the  action  being  intensified 
by  the  frozen  condition  of  the  upper  layers  of  the  Chalk.  Within 
the  area  invaded  by  the  ice-sheet  this  surface-deposit  was  not  likely 
to  remain  undisturbed,  but  in  the  inner  recesses  of  the  Wolds,  never 
reached  by  the  North  Sea  ice-sheet,  such  a  deposit  has  accumulated 
in  high-lying  depressions  and  also  in  the  upper  reaches  of  some  of 
the  Wold  valleys,  where  it  has  remained  unmodified.  The  analogy 
between  such  deposits  and  the  Coombe  Bock,  already  referred  to,  is 
obvious,  though  this  formation  may  have  been  going  on  throughout 
a  great  portion  of  the  Glacial  Period. 
