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The first point then where we pause, shall be on a knoll of 
rising turf not far from Twerton Gaol, and at the distance of 
about half-a-mile from the river Avon. Standing here at an 
elevation of some 89ft. above the level of the present river, we 
should hardly expect to meet with gravel, but on looking into the 
cutting we see men at work in a fine bed of that material ; in fact 
the whole of this rising ground is made up of a gravel deposit. 
How and whence then did this gravel come so far above the 
present bed of the stream? The Avon, as Sir Roderick 
Murchison said, is now the “ mud-collecting Avon ;’ can- this 
gravel then be water-born? If so, the features of the landscape 
must have been far different to what they are now ; and indeed, 
great changes, both in the climate and the outlines of the surface, 
have taken place since then. This is evident from two facts 
which a little investigation discloses. We look more closely at 
this gravel and see that it consists ofa mixture of the débris of the 
various formations in our immediate neighbourhood, with here and 
there remains of rocks which are to be sought for at a considerable 
distance. We find for instance rolled pebbles of Oolite and Lias; 
the débris of our surrounding hills and valleys ; lower down are 
rolled and sub-angular flints, with occasionally a small rolled 
pebble of chalk, for these we must look to the more distant 
Chalk hills as the source ; still lower down we come upon 
rounded and sub-angular pebbles of Mountain limestone and 
reddish sandstone, for these we must go to our Mendips and the 
Coal Measures ; and finally, at the base of all, resting slightly 
buried in the mottled clays (about 5ft. thick), are sub-angular 
masses of a hard quartzose greenish sandstone, and large boulders 
of Inferior Oolite. One of these measured during a Tuesday’s 
walk was 2ft. 5in. long, 2ft. 4in. broad, and 1ft. thick, containing 
rather more than 53 cubic feet, and weighing about 73 ewt. 
(reckoning 156lbs. to a cubic foot). 
Now what do we argue from these facts? First, that this 
thick bed of gravel, if deposited by water, indicates that the 
