SOME REMARKS ON THE PLEISTOCENE MAMMALIA. 7
the oldest river deposit at Grays, are interesting as being
intermediate in character between the true cave bear and its
presumed ancestor.
Hippopotamus.—Of all the Mammals which occur abund-
antly in the Pleistocene fauna of Britain, none seems so difficult
to understand as the hippopotamus. As shown by the discover-
ies in a river deposit at Barrington, near Cambridge, it certainly
settled and bred in this part of Europe. Prestwich once suggested
that the race which dwelt here may have been protected with
hair or wool, but even so it could scarcely have lived in water
which was liable to be frozen for a large part of the year. For
the latter reason the presence of hippopotamus has usually
been assumed to imply at least a warm-temperate climate in
these latitudes at the time. Quite lately, however, Mr. Marius
Maxwell has found in the Lorian Swamp in Kenya Colony,
East Africa, a race of hippopotamus which he describes as
having "taken up practically a terrestrial mode of life."16
It lives in a "desert-like country hemmed in by the thick prickly
bush through which it cannot pass." The adaptability of the
animal is therefore greater than has hitherto been supposed,
and the race which formerly inhabited Britain may have been
able to endure the rigours of a comparatively cold winter,
without needing water in which to swim and wallow.
Deer.—The deer of the Pleistocene period illustrate well
the remark that at this time the Mammals reached their extreme
development. Most of them have antlers of astonishing
size and stoutness. Like some of the earliest Pleistocene forms
(e.g. Cervus verticornis from the Norfolk Forest Bed), the
Irish deer (Cervus giganteus) exceeds all existing deer in the
size and weight of its antlers. Its remains occur both in the
older deposits of Grays and Walton and in the later deposit
of Ilford ; while it survived at least until the Neolithic period
in Ireland. The extinct fallow deer (Cervus browni), first found
at Clacton, and subsequently in the London district at Turnham
Green17 and Charing Cross,18 is much larger than its surviving
representative. Most of the remains of the red deer or stag
16 Marius Maxwell, Abstract Proc. Linn. Soc., no. 430, 20th March, 1924 ; also Stalking
Big Game with a Camera in Equatorial Africa, London, 1924.
17 G. Busk, Quart. Journ. Geol. Soc., vol. xxviii. (1872), p. 468.
18 A. S. Woodward, Geol. Mag., 1917, p. 424.