SUPERFICIAL DEPOSITS. 225 



carried considerable distances, and the clay, with its included 

 fragments, has been deposited far beyond the foot of the 

 slopes. For example, to take an instance I have already 

 brought forward,* and which has also been noticed by 

 Prestwich.f La Motte or Green Island is an islet off the 

 south-east coast of Jersey, surrounded at about half -tide. It 

 has a base of hard, unweathered, undecomposed diorite, on 

 which lies some ten to fifteen feet of yellow clay, containing 

 a few angular and sub-angular fragments of diorite and red 

 granite. La Motte is some 300 yards beyond spring tide 

 high water mark, and inland the ground is perfectly level for 

 about half a mile before it begins to rise very gently to the 

 high table land. Such an instance alone, without reference 

 to other evidence, would put the mere action of rain wash 

 entirely out of the question. 



As is well known, Prestwich maintained^ that in post- 

 glacial times a subsidence of western Europe and the 

 Mediterranean coasts took place. After a short period of 

 submergence there was a sudden upheaval, or the land rose by 

 a series of sudden lifts. This produced a rush of water off 

 the rising ground, and the tumultuous currents swept down 

 the surface debris and deposited it at varying distances. This 

 deposit is the "rubble drift," of which our yellow clay, or 

 brick earth, with its fragments, forms part. Strong affluent 

 currents, caused by a sudden upheaval of our islands, would 

 certainly go far to explain many of the characteristics of our 

 clay and its contents, more especially its appearance on the 

 hill sides, and its wide spread. But such a rush of water, 

 or even a series of rushes, would hardly, I think, be suffi- 

 cient to account for the rounding of its constituent grains, 

 nor would the fine stratification occasionally observed be at all 

 likely to be laid down by a rapid, headlong current. Again, 

 it is difficult to see how the raised beaches, or at least beds of 

 rolled stones, found in the body of the clay, could be deposited 

 under such conditions, and also the presence of flints would 

 not be accounted for, unless under the supposition that they 

 had been already deposited during a previous submergence. 

 In this connection it may be remembered that pieces of granite 

 and other rocks, originally far from the locality, have been 

 found in the rubble drift or its equivalent near Worthing and 

 on Hayling Island. The rush of water caused by sudden 

 upheaval would not be sufficient to account for their presence 

 there. 



* " On the Jersey Brick Clay." Op. cit. 

 t " On the Evidences of a Submergence of Western Europe, &c." Op. cit. 

 t See papers already referred to, also his book " The Tradition of the Flood." 



