DE. HICKS— PEE-HISTORIC MAN IN SEXTAIN. 
149 
manufacture being tbus clearly explained. These flakes occurred 
beneath sand and brick-earth along with bones of rhinoceros, etc. 
In addition to the unabraded implements, very many have been 
discovered scattered about in the gravels of the Thames Yalley, 
with indications of having been rolled by water-action. Many 
of these have been obtained from the lowest deposits which rest 
on the irregular floor formed by the London Clay. It is therefore 
evident that man must have occupied this area before the gravels 
were deposited; hence it is important to know to what period they 
should be assigned, and by what agencies they were accumulated. 
By most authorities these gravels have hitherto been classed as 
of Post-glacial age, but some, notably the late Mr. Belt,* have tried 
to prove that they are in reality continuous with, and of the same 
age as, the acknowledged glacial deposits which spread over the 
hills to the north of the valley. Mr. Belt has demonstrated by 
numerous sections the similarity in tbe character of the gravels and 
brick-earth in the Thames Yalley with the glacial drift found at 
Hendon, Finchley, Whetstone, etc., in Middlesex, and has given 
many reasons why he considers that they should not be classed with 
ordinary river-deposits. We examined many of the sections in these 
districts together, and found the glacial deposits mantling the hills and 
descending the slopes into the valleys in many places to the level of 
the higher Thames-Yalley implement-bearing gravels. Since that 
time I have had opportunities of examining many fresh sections on 
the plateaux and along the slopes at Kingsbury, Hendon, Finchley, 
Whetstone, etc., with similar results, proving that the main features 
are due to the underlying irregular floor of London Clay. Evidence 
is therefore constantly accumulating, tending to show that the high- 
level gravels and the overlying brick-earth, from having so much in 
common with the glacial drifts, must be considered as belonging to 
the Glacial period. They are found, on comparison, to have little 
or nothing in common with the recent deposits in the Thames 
Yalley, and are altogether unlike any ordinary river-accnmnlations. 
Moreover, it must not be forgotten that very little change has 
taken place in the level or position of the Thames during the his¬ 
toric period, and that, except under such very great changes as took 
place during and at the close of the Glacial period, accumulations 
of this kind could hardly have been spread out over such extensive 
areas. 
The occurrence of an unstratified deposit, containing large stones, 
at the base of the gravels in the Thames Yalley, agrees so exactly 
with the conditions witnessed everywhere in the glacial drift at 
Hendon and Finchley, that one is inclined to refer this deposit to a 
very early phase in the Glacial period. It is, in reality, all that 
remains of the lowest boulder-clay, and, as it consists mainly of 
local materials, it may he considered the local till. In the Thames 
Yalley, as on the plateaux in Middlesex, these lowest deposits are 
covered by more or less stratified sands and gravels (the so-called 
middle sands and gravels), and upon the latter in the Thames 
* ‘ Quarterly Journal of Science/ July, 1878. 
