THE NEW RAILWAY BETWEEN UPMINSTER AND ROMFORD. 9
Street, is by no means either slight or obscure, and it seems to me
quite sufficient to warrant us in regarding them as River Drift, unless
there should be strong special evidence to the contrary. And, on
the other hand, the decided presumption that they are River Drift
derives additional strength from what seem to me to be the very
slight grounds for the formation of an adverse opinion.
For if the gravel, sand, and clay much resemble the material and
arrangement of the beds below the. Upper Boulder Clay of Hendon
and Finchley, they equally suggest the gravel, sand, and loam which
are the usual constituents of river drifts, as well as the order in
which they usually occur. And when we remember that the beds
under the Finchley Boulder Clay are some five miles away, and are
found only at heights of more than 200 feet above the sea, it seems
to me that nothing but the finding of unquestionable Boulder Clay
capping the beds at Endsleigh Street could establish a real affinity
between them and the deposits at Finchley. "Race," also, may be
found in these Finchley beds; but it may also be seen in clays and
loams of the most diverse ages. Readers of the chapter on the
Woolwich and Reading beds in Mr. Whitaker's memoir from which
I have already quoted, may note that "race" is mentioned as exist-
ing in clay or loam in at least ten different sections. And if we turn
to that on River Drift we find that "race" was found in many
sections in the unquestionable River Drift of Ilford, Erith, and
Crayford. Thus its presence furnishes no presumption whatever as
to the age of any bed in which it occurs; but leaves that question to
be decided on the general evidence, which seems to me wholly in
favour of the River Drift view.
It may be worth while to add that Mr, Hudleston (Proc. Geol,
Soc.) remarked after the reading of Dr. Hicks' paper that "so long
ago as 1715, the Mammoth was found in deposits on the same
plateau (at Gray's Inn Lane) along with a Palaeolithic implement."
I now return to Hornchurch. There are two points on which I
should like to add a few words in connection with this Hornchurch
Boulder Clay, and the conclusions deducible from its presence there.
Firstly, in the discussion on my paper at the Geological Society last
March it was remarked that the river deposits of the Thames valley
were not really terrace gravels at all. Now, it is quite true that if
anyone tries to map the boundaries of the various terraces at and
south of Hornchurch, he will soon find himself engaged in a hopeless
task, a hank which appears comparatively clear and sharp at a given