OF WESTERN EUROPE AND THE MEDITERRANEAN COASTS. 
907 
where layers of light earthy chalk debris alternate with others of heavy splintery 
flints, as in the case of the mass of Rubble-drift (or head) overlying the Raised beaches 
of Brighton and Sangatte. 
The Brighton beach abuts, like the recent one, against a cliff, over which the drift 
was shot from the uplands above, not in one sweep, but in a succession of throws, some 
of which were of sufficient force to move large masses of flints and great blocks of 
Tertiary sandstone from a distance of two to three miles inland, whilst others had only 
force enough to carry down the lighter chalk rubble, and impalpable marly sediment often 
finely laminated, showing that it was deposited in water, and in water, at the time, 
comparatively still. W e thus have, as it were, a measure of the forces in operation 
during the upheaval, for as the divergent currents, caused by the upheaval of the 
land through the superincumbent body of water, would vary in velocity and power 
according to the rapidity of the upheaval, it is evident that the weight and quantity 
of material moved will be in accordance with the strength and length of those 
currents. The variations in the structure of the “ head ” show the movements to 
have been alternately slow and more rapid, or by fits and starts, though, as there is 
no break in the continuity of the deposit, it is probable that they were continuous or 
nearly so. It is also obvious that a body of water 1000 feet or more deep, moving 
even slowly oft the land, would have formed an engine of enormous power, and as I 
have before remarked, capable, like Nasmyth’s hammer, of exerting that power with 
the gentlest touches or with almost irresistible force. For the fuller discussion of 
these points, I must, however, refer to the paper before mentioned, in which these 
points are described more fully.* 
In that paper I have shown that the Rubble-drift is very widely, though generally 
very sparsely, spread over the South of England. I now propose to show that it may 
be traced over much of Western Europe and the Mediterranean coasts (see Plate). My 
own personal observations are limited to parts of France and Italy. I have, however, 
the less cause to regret this circumstance, as some of the principal exhibitions of it 
have been explored by other geologists in a way which would have been difficult for 
a single individual to have accomplished, and their evidence is free from the bias 
which might be supposed to attach to the advocate of a theory. At the same time 
there is the disadvantage, that without attention being specially directed to this 
particular drift, some of its phases may easily be overlooked and passed by, so that 
further research may prove it to be far more general than here described. It is also to 
be observed that in continental areas we meet with fresh phases of the rubble-drift, 
which, while differing from what we find in England, equally bear testimony in tbe 
same direction. 
* ‘ Qnr,rt. Jcnrn. Geol. Soc.,’ vol. 48, p. 331. 
5 .^ 2 
