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PROCEEDINGS  OF  THE  GEOLOGICAL  SOCIETY. 
[May  1893 
past  to  find  boulders  of  Scandinavian  origin  in  Eastern  England. 
The  Bhomben-porphyr  of  the  neighbourhood  of  Christiania,  for 
instance,  has  been  fairly  identified  as  an  erratic  on  the  coast  near 
Cromer.  Very  recently  a  member  of  the  Danish  Geological  Survey 
obtained  three  specimens  of  boulders  in  the  same  district,  of  which 
one  was  thought  to  have  come  from  the  south  of  Norway  and  the 
other  two  from  so  remote  a  district  as  Dalecarlia  :  they  were  either 
felspar-  or  felsite-porphyries.  The  subject  of  Scandinavian  boulders 
has  been  likewise  discussed  by  Mr.  Lamplugh  in  his  paper  on  the 
Drifts  of  Elamborough  Head,  where  he  quotes  Mr.  Harker  to  the 
effect  that  the  bulk  of  the  granitic  and  gneissic  specimens  might 
have  been  derived  from  Scandinavia  or  from  the  Scottish  Highlands. 
Among  them  are  some  undoubted  Norwegian  rocks,  while  none 
can  be  pointed  out  as  certainly  brought  from  Scotland  :  it  may  well 
be,  then,  that  the  whole  of  the  doubtful  rocks  are  also  of  Norwegian 
origin.  The  granite-and-gneiss  group  of  Elamborough,  according  to 
Mr.  Lamplugh,  amounts  to  between  3  and  4  per  cent,  of  the  boulders 
at  that  spot.  If  one  might  venture  to  make  a  remark  on  this 
subject,  it  would  seem  that  the  felspar-  and  felsite-porphyries,  rather 
than  the  granites  and  the  gneisses,  are  the  most  likely  rocks  to 
survive  the  long  journe}T  across  the  North  Sea. 
One  of  the  most  curious  facts  in  connexion  with  Northern  Drift 
is  the  discovery,  narrated  by  Mr.  Whitaker,  of  a  deep  channel  of 
Drift  in  the  valley  of  the  Cam,  also  in  Essex.  The  Drift  here  is 
said  to  consist  mostly  of  loam  or  sand  more  or  less  bedded,  together 
with  clay  (sometimes  apparently  a  Boulder-clay  full  of  pieces  of 
chalk)  and  gravel.  At  Newport  occurs  the  greatest  thickness  of 
Drift  hitherto  recorded  in  the  South-east  of  England.  In  one  case 
a  boring  of  340  feet,  being  140  feet  below  the  level  of  the  sea,  failed 
to  reach  the  bottom  of  this  curious  rift  in  the  Chalk.  In  this  case 
we  seem  to  be  dealing  mainly  with  beds  below  the  great  sheet  of 
Boulder-clay,  and  thus  the  chief  interest  in  these  singular  disco¬ 
veries  centres  in  a  period  anterior  to  the  deposition  of  that  formation. 
The  Bev.  Edwin  Hill  drew  attention  to  some  features  of  the  Boulder- 
clay  of  the  adjoining  district  of  West  Suffolk,  inferring  that  it  must 
contain  within  its  mass  pervious  beds  or  seams  of  some  different 
material,  and  consequently  that  it  is  not  a  uniform  or  homogeneous 
mass.  From  the  above  considerations  he  argued  that  this  Boulder- 
clay  could  not  be  the  product  of  the  attrition  between  an  ice-sheet 
and  its  bed — a  conclusion  on  the  part  of  the  Author  apparently  not 
shared  by  the  majority  of  those  present  at  the  reading  of  his  paper. 
