NEW RAILWAY-CUITING AT GUILDFORD. 607 
Our southern downs had not then been travelled and swept over 
by drift, and rounded down by ice-action for the last time, and 
the country must originally have presented far sharper and steeper 
features and numerous ravines. The relief of the former features 
now brought to ight, the irregular closely undulated surface of the 
Tertiary clays here exposed for many yards, is in remarkable con- 
trast to the regular, long, beautifully sweeping curves of the present 
surface; and the greater part of the valley of the Wey and its 
tributaries, south of the chalk range, has been lowered certainly to 
the extent of 60 feet since the sands preserving this old terrestrial 
surface were deposited. 
The impression made upon my mind by the contemplation of these 
sands is, that they were deposited in an old re-entering bend on this 
side of the gorge at a time when the old river-bed of the Wey stood 
at about 60 feet above its present level, which river then washed 
the base of a steep scarp of chalk on this side. ‘The ancient level, if 
extended south, is close upon the site of the old castle, and crosses 
the High Street, Market Street, top of North Street to the old 
quarry east of Chertsey Street; and I imagine that the chalk point 
or spur then existing and overlooking the ancient river occupied a 
position between the Quarry and Aldersey Place, thrown off from 
much higher hills with sharper outline where the Merrow Downs 
now are. As the fluvial deposits were carried through the gorge 
and spread out over the flats to the north, the slope of the bed was 
becoming less: this is evident from the fact that the upper beds are 
the finest. (The Thames valley itself was rapidly filling with de- 
tritus on the north.) Such a re-entering bend of a river is precisely 
the spot where the carcasses of animals that have lived on the higher 
reaches of a river are occasionally floated in, sink and become 
buried in the silt; and this is where, in the present case, nearly all 
the mammalian remains have been exhumed. They are to be dis- 
tinguished from remains of the same fauna found in the later drift, 
_ often, limagine, derived from an intermediate resting-place. I would 
in this place call attention to the fact that this re-entering bend of 
the old river has its counterpart in a similar bend of the river now, 
and due north of this point. 
The greatest thickness seen of these high-level sands is 32 feet, 
which gives the highest bed an altitude at Cross Lanes of 100 feet 
above the river Wey, or 200 above the level of the sea, the height of 
the base being very constant, only varying with the slight original 
north-westerly slope of the old clay surface and its minor undulations. 
On the deposition of these sands coming to a close, and towards 
the end of the period, the river had, from being broad and rapid, 
passed to more sluggish conditions; there was a change. An eleva- 
tion of the country probably took place to the south, possibly, though 
not necessarily, with a corresponding depression upon the axis-line 
of the Thames valley, which led to the removal of the greater part 
of these earlier old river-graveis and sands in front of the gorge, 
leaving the remnant lately disclosed. Then commenced the further 
deepening of the tributaries on the south, and that of the gorge 
