368 — SECTIONAL TRANSACTIONS.—C. 
After the Pliocene uplift had led to over-deepening, the Glacial period began to 
alter the landforms and to modify the inhabitants. 
Man then appeared, and the long-continued struggle to survive by subduing nature 
commenced. Little is known about him except that almost from the start he had a 
true eye for form and could not, or at any rate did not, resist the impulse to make 
his implements beautiful as well as useful. He depended upon raw material for the 
selection of his dwelling-place, and it was only where flint occurred in abundance that 
he could make his weapons, and this distribution led to the selection of sites for occupa- 
tion mainly below the Goring Gap. 
Good water has always been a necessary of life, and the London area is well placed 
for good supplies. First, the river and its tributaries ; next, the springs rising from 
the base of the terrace gravels ; finally, the artesian water from the Chalk. The last 
supply has been drawn upon in increasing quantities; the over-pumping resulting 
in a permanent depression of the water-table and a progressive depression that 
continues and increases as more boreholes are sunk. Formerly the water from the 
Chalk rose under pressure, through the overlying Tertiary Beds, above the surface ; 
but to-day, under parts of the City and in Westminster, the water-table is below the 
top of the Chalk. The rate of fall is locally over 3 feet per annum. The exhaustion 
is augmented by great boreholes in the collecting ground of the Chalk outcrop along 
the North Downs and the Chilterns, and it may be that the basin will become nearly 
dry in course of time. This and the difficulty of disposing of sewage will tend to 
restrict the growth of the town. 
The second part of the lecture (S.W.W.) deals with the structural and physiographic 
evolution of the London Basin as a unit. Attention is called to the systematic 
variation in the thickness of the several Eocene formations which, studied by means 
of isopachyte maps, renders it possible to trace the stages of growth of the main 
syncline and the minor structural features within it. 
The later stages of development may be regarded as beginning with the trans- 
gression of the Pliocene sea into the main synclinal area. There followed a series 
of uplifts alternating with periods of base-levelling, recorded in the form of a number 
of dissected platforms or peneplains whose dates are known within reasonably narrow 
limits and whose history, including also that of the glacial deposits, forms a natural 
prelude to that of the Thames terraces at a lower level. 
Mrs. Ross.—The Physiographic Evolution of the Kennet-Thames. 
A short account of the river terraces of the Lower Thames and its tributaries is 
given, indicating their distribution both in plan and profile. The established terraces 
of the Thames (the Boyn Hill, Taplow and Flood Plain) have been traced up-stream 
into the Kennet Valley. Evidence is cited to establish two terraces above the Boyn 
Hill among the gravels now classed as ‘ Glacial’ or ‘ Plateau.’ These it is proposed 
to name the ‘ Winter Hill’ and ‘ Binfield ’ Terraces. 
Mr. J. F. Kirxatpy.—The Classification and Correlation of the Lower 
Greensand of the Western Weald. 
This paper summarises the results of a piece of work which has involved the 
complete revision on the 6-inch scale of the area around Hascombe, a detailed critical 
examination of the area east of Guildford, in which particularly interesting features 
are shown, and an outline survey of the Bargate-Sandgate Beds and associated strata 
throughout the Weald. 
Some of the chief points at issue are :— 
(i) The non-coincidence of the ‘ Bargate Stone’ (s.s.) with the ‘ Bargate Beds,’ 
the strata having been clearly subject to irregular original calcification and patchy 
subsequent decalcification. 
(ii) The widespread occurrence throughout the Western Weald of a phase of 
calcareous beds in the Parahoplites nutfieldensis sub-zone. 
(iii) The existence of pre-Folkestone axes of warping which have very clearly 
influenced the lithology and thickness of the Bargate and associated beds. Renewed 
movement along some of these axes has affected the present physiography. 
(iv) The correlation of the so-called Loamy Folkestone Beds with the Sandgate 
Beds. 
(v) The existence of an important physical break at the base of the Folkestone 
Sands. 
