26 
The Ancient Fauna of Essex. 
wearing action ; for all the angles and ridges of the bones 
still retain their original natural sharpness.” 13 
If we could once more restore the physical features of the 
Valley of the Thames as it existed in Pleistocene times, we 
should doubtless find that all those places along its lower 
course, where considerable deposits of brick-earth occur and 
where the remains of the larger Mammalia are found in such 
abundance, as at Ilford, Grays, Erith, &c., mark the sites of 
ancient bays formed by the debouchment of side-valleys into 
the principal one, giving rise in flood-times to eddies into 
which the floating carcases of land-animals would indubitably 
be drawn, and would in course of time sink and become 
entombed in the soft and yielding argillaceous mud beneath. 
That many of the remains of land-Mammalia met with in 
these deposits may have lain for a very long period of time 
upon the surface of the dry ground before being carried down 
by floods and entombed in their present resting-place is, I 
think, rendered highly probable by the following interesting 
observation made by Mr. Wm. Davies, F.G.S., of the British 
Museum of Natural History, who writes as follows:— 
“During the preparation of fossil remains from the brick- 
earth, I have had frequent opportunities of noticing points 
which would otherwise have passed altogether unobserved by 
any one, as they could only have been seen at the time the 
specimen was being actually cleared and developed from its 
sandy or argillaceous matrix. 
“I observed, for example, in the skulls of several fossil 
Oxen numerous shells of the common Land Snails, Helix 
nemoralis and H. hortensis, in one instance more than thirty 
examples, all in good condition. 
“I cannot help imagining that these snails, whilst still 
living, may have found their way into the hollow cavity of 
the skull through the only aperture (the foramen magnum) 
for the purpose of hybernation—as is common with all 
Helices now living in this country—whilst the skull was still 
lying on the dry land, where it may have been left for a long 
time after a flood; or, the animal to which it belonged may 
18 See “Notes on the Pleistocene Deposits yielding Mammalian remains 
in the vicinity of Ilford, Essex.” By Henry Woodward, F.R.S., and 
William Davies, F.G.S. (G-eol. Mag., 1874. Decade II., vol. i., pp. 
390—398). 
