NEW RAILWAY-CUTLTING AT GUILDFORD. 609 
in the geological history of a large area north of the Wealden denu- 
dation.” ‘lhe older land-surface now exposed at Guildford is another 
and still earlier phase of those conditions, a link in the chain of 
evidence which renders the first less isolated, and may lead eventu- 
ally to the correlation of geological events of this age as displayed in 
other areas more easy of interpretation. 
I have already connected the level of the basement gravels with 
the narrow terrace or step on the side of the hill overlooking the 
Wey on its right bank just within the gorge at Quarry Street ; and 
if we follow this level round the valley to the south-east, we see it 
showing again at the points or spurs of the Lower Greensand near 
the opening of the Tillingbourne valley; it is represented very 
plainly, from near the base of the steep slope of the Greensand up 
to the next fall to the present stream (the outcrop of the Neocomian 
clay), by the well-marked high-level terrace which extends as far as 
Halfpenny Farm and Chilworth Manor ; this terrace is not so defined’ 
higher up the valley, where the ground is much more broken and 
cut into by lateral drainage-lines. If we suppose the drainage- 
fall of the country to have remained tolerably constant (though the 
character of the sands north of Guildford would show that the fall 
was greater) whilst the streams worked into it, and apply about 60 
feet to the level of the Tillingbourne at the Chilworth Mills, which 
are 140 feet above the sea, the 190-feet level lies on the terrace 
above, and the 200-feet level is as nearly as possible that of the base 
of the next and principal escarpment of the sands. The discovery by 
Dr. Buckland, accompanied by Mr. Godwin-Austen, of the bone of a 
Rhinoceros * in loam on the side of the Greensand escarpment, and 
at some height above the massive slopes of drift on the banks of the 
Tillingbourne, was not improbably ina small remnant of beds of the 
age of the Guildford high-level sands, which in such a position would, 
from their sandy nature, be very difficult to distinguish from the 
subjacent Greensand, that being probably covered by surface-wash 
of the same sands. JI think this is a more likely explanation of the 
different levels at which the gravels have been noticed in the above 
valley than that alluded to in a footnote on the same page, viz. of 
longitudinal fractures having occurred in it since the deposition of 
the drift and gravel. Inthe diagrammatic section (fig. 9), where the 
elevation of the hills has been greatly exaggerated, I have attempted 
to show the different drainage-lines of old surface (No. 1, the oldest ; 
No. 2, the intermediate ; No.3, the present) and their corresponding 
gravels (No. 1, the high level north of Guildford, and No. 2, the 
Pease Marsh), as well as the drift, distinguishing the difference of 
outline or probable relief of the country in past and present times. 
On the right bank of the Wey, within the gorge, the same line of 
level shows itself on the Portsmouth road on passing St. Catherine’s — 
Hill by Brabceuf. The high-level gravels of the Tillingbourne at 
Shalford, near its junction with the Wey, range from 110 to 130 feet 
above the sea, and are therefore of a later date, and to these belong the 
* Murchison, Quart. Journ. Geol. Soc. vol. vil. p. 378 (1851), 
