in the Drift of the Valley of the Avon. 227 
since perished. Again, what more typical emblem of fragility 
than an egg shell, still we find fragments of bird’s eggs carefully 
preserved even indicating the position in which they sank to the 
bottom and rested for countless years, until brought to light by 
the restless hand of science. 
Not only do the fossil remains bear witness of the manner in 
which the clay was formed, but an examination of the mammalian 
Fauna strongly corroborates the statement, that the climate of our 
island then resembled that of the Arctic Regions of the present 
day. Hence there is nothing strange or unaccountable in the pre- 
sence of the Reindeer, Musk Ox,! Ringed Lemming, Marmot, the 
Woolly-coated Mammoth and Rhinoceros, creatures all peculiarly 
adapted for a cold climate. 
The fluviatile origin of these drift deposits and the idea of the 
former existence of rivers of such magnitude, may appear to many 
persons as at best, a mere speculation just within the limits of possi- 
bility, but far too bold to admit of anything like definite proof. 



Let us then briefly enquire how far facts accord with the proposed 
-explanation, and for the sake of convenience let us examine the 
deposits situated between the two ranges of chalk hills, having 
Harnham on the south, and the Devizes road on the north. 
Between these two points the chalk valley is partially filled up with 
| various admixtures of gravel, sand, and clay ; the gravel is spread 
_ over the central position ; sand and numerous small fragments of 
_ rolled chalk predominate on the south, whilst the clay and brick- 
earth is chiefly found on the north side, in some parts attaining 
the thickness of nearly 30 feet; an excellent section of this clay is 
exposed in the pits worked by Mr. Harding and by Mr. Baker. 
_ At the present day streams flowing over soft soils (or even hard 
rocks,) are constantly wearing away more or less, sand, mud, 
and stones; any cause which impedes the current, such as banks, 
curves in the river, &c., favors the deposition of the mud, sand, 
or those materials which are comparatively light. It is clear then 

1The Musk Ox has not as yet been discovered at Fisherton, its presence as a 
fossil in our Wiltshire drift, has however been elsewhere recorded by Mr. 
Cunnington. Wilts. Mag: vol. iy. 
