2 THE ESSEX NATURALIST.
Clacton, Walton, Grays and Ilford.1 There are others just over
the border of the adjacent counties. The subject to which I
refer is therefore appropriate for the consideration of the Club,
and I should like especially to emphasise its difficulties. The
palaeontologist's report on the remains submitted to him is, I
fear, often most disappointing. The disabilities under which he
works scarcely permit it to be otherwise. With material for
comparison, or even with drawings such as those published by
Hue2 it is easy to name the bones and teeth approximately,
but it is often not possible to interpret them more precisely.3
The foremost of the difficulties is due to the fragmentary
nature of the specimens. In the river deposits, such as those of
Essex, there rarely occur more than the isolated bones and jaws
of disintegrated skeletons which have been scattered by cur-
rents or heaped together by eddies. In the caves, the remains
have sometimes been washed together by running water, but
more usually they are the leavings of the food of man or hyaenas.
Very few comparatively whole skeletons have hitherto been found
in this country.
Next, it must be remembered that in this part of the world
the mammals were living under most varying conditions. During
the Pleistocene period the southern limit of glaciation frequently
changed, and the specially variable zone included what is now
the southern half of England and the middle part of Europe.
At the present day most of the Mammals which happen to be
widely spread in such a country as Africa exhibit great varia-
bility according to the circumstances under which they live.
Some species are even separated into several distinct races or
sub-species. In the inhospitable forests, plateaus, and tundras
of Alaska4 (which are probably much like Britain was during the
greater part of the Pleistocene period), the variability of each
species of Mammal seems to be even greater according to cir-
cumstances, and there are still living endless gradations between
the various forms.
Thirdly, we now know the Pleistocene Mammals sufficiently
1 W. Davies, Catalogue of the Pleistocene Vertebrata, from the neighbourhood of Ilford,
Essex, in the collection of Sir A. Brady. London, 1874.
2 Edmond Hue, Music Osteologique : etude de la Faune Quaternaire : osteometrie des
Mammiferes. Paris, 1907.
3 For valuable general observations on the Pleistocene Vertebrata of Europe, see M. Boule,
Les Grottes de Grimaldi (Baousse-Rousso), vol. ii. Monaco, 1921.
4 W. H. Osgood, Biological Investigations in Alaska and Yukon Territory. North American
Fauna, no. 30 (U.S. Dept. Agriculture, 1909). See also F. C. Selous, Recent Hunting Trips in
British North America. London, 1907.