PEBBLES  FROM  THE  GLACIAL  DRIFT. 
317 
Yol.  49.] 
seen  either  a  red  quartzite-pebble  or  a  block  of  white  quartz  or  of 
igneous  rock  in  them.  Between  Staines  and  Chertsey  there  is  a 
stretch  of  Thames  Gravel,  and  in  it  are  hard  reddish-brown  quartzites 
and  vitreous  greyish-brown  quartzites  of  Glacial  Gravel  character. 
I  have  noted  shallow  workings  at  Thorpe  Lee. 
St.  George's  Hill,  near  Weybridge,  is  capped  by  Southern  Drift, 
and  the  plateau,  100  feet  O.D.,  between  Walton  and  Weybridge,  is 
capped  by  gravel  seemingly  derived  from  the  Southern  Drift.  In 
this  gravel  I  could  not  find  any  red  quartzites,  but  Lower  Greensand 
fragments  are  abundant. 
I  have  not  found  any  sections  in  the  gravel  between  Walton  and 
Molesey  ;  and  the  next  locality  to  which  1  wish  to  draw  attention 
is  Kingston  Hill  (178  feet  O.D.).  There  are  sections  near  Thatched 
House  Lodge,  in  Kichmond  Park,  and  in  the  great  gravel-pit 
south  of  Warren  House,  described  in  the  Proc.  Geol.  Assoc, 
vol.  vi.  (1880)  p.  371  ;  and  I  also  found  a  good  section  on  the 
southern  side  of  the  hill  at  Coombe  Warren,  about  150  feet  O.D. 
They  all  show  roughly-stratified  sandy  gravel  containing  both  red 
quartzites  of  the  Glacial  Gravel  type  and  Lower  Greensand  frag¬ 
ments  from  the  south. 
On  Wimbledon  Common  there  is  a  very  similar  gravel,  which 
attains  a  level  of  180  feet  O.D.,  and  here  I  found  red  quartzite- 
pebbles  in  many  places.1 
The  latitude  of  the  Coombe  Lodge  pit  is  51°  2 o'  X.,  and  the 
most  southerly  patch  of  Glacial  Gravel  indicated  on  the  map  is  near 
Iver,  51°  31'  north  latitude.  The  level  is  about  the  same  as  that  of 
the  Kingston  and  Wimbledon  patches  ;  so  perhaps  we  should  look 
upon  these  latter  as  Glacial  Gravel.  In  any  case  I  believe  them  to 
be  on  the  southern  boundary  of  the  area  over  which  Glacial  Gravel 
debris  are  distributed. 
Note. — For  doubts  as  to  gravel  classification,  see  Whitaker, 
‘  Geology  of  London,’  vol.  i.  pp.  296,  300. 
IX.  Dartford. 
East  of  Wimbledon  the  high  ground  is  much  built  over,  or  it  is 
covered  by  gravel  apparently  almost  wholly  derived  from  the  Black- 
heath  Pebble  Beds,  or  it  is  formed  by  those  beds  themselves.  But 
at  Dartford  Heath  there  is  a  gravel  in  which  pebbles  of  red  quartzite 
and  other  material  from  the  Glacial  Drift  are  abundant.  I 
have  had  the  advantage  of  visiting  that  locality  in  company  with 
Mr.  F.  C.  J.  Spurred,  F.G.S.,  who  will,  I  hope,  soon  describe 
the  sections  at  length.  I  merely  therefore  mention  that  in  all  the 
pits  I  found  red  quartzite-pebbles,  and  in  most  places  Lower 
Greensand  fragments  from  the  south  as  well.  At  Wansant  Farm 
the  gravel  is  very  thick,  and  in  the  bottom  bed  I  found  a  pebble  of 
basalt,  rounded  and  much  decayed  externally,  about  2  inches  in 
1  See  Prestwich,  Quart.  Journ.  Geol.  Soc.  vol.  xlvi.  (1890)  p.  159. 
