2GG JOSKPH PRESTWICH, f.R.S., F.G.S.^ ON A POSSIBLE 



The explanation which I would sugo-est and Avhich seems 

 to me best to satisfy all the conditions of the problem is that 

 the special character and position of this Rubble-drift are due 

 to the submergence and subsequent re-elevation of a land sur- 

 face, whereby the Fauna and Flora of the submerged area 

 were destroyed, and their remains dispersed over the sur- 

 face of the submerged land. As that surface emerged from 

 beneath the waters, the scattered remains of that fauna, 

 together with the loose land debris, were swept together 

 down the slopes of the hills and into the valleys, leaving 

 traces or isolated portions in any cavities or hollows over 

 which the Rubble passed. The stone implements and 

 weapons of Quaternary Man left and lost on the old land 

 surface, would necessarily be mixed up with the general 

 mass of debris, as would also human remains where Man 

 had failed to escape. That such may have been the case is 

 shown by the circumstance that the Rubble-drift contains tlie 

 remains of the various Quaternary animals living at the time 

 of its formation, together with, in places, Flint Implements 

 of human workmanship, and in a few rare instances portions 

 of the human skeleton itself. Although tlie several forms of 

 the Rubble-drift differ widely in aspect and have been referred 

 to different agencies, they are all concordant and admit of 

 explanation by reference to one common cause. The follow- 

 ing are the more common forms of this Drift in England. 



The Aneinlar Rubble or ^'' Head" over the Raised Beaches. — 

 This, which is the commoner form of this Drift in this 

 country, has accumulated in hollows on the surface or 

 under the lee of the old cliffs of the Riised Beaches. Owing 

 to the existence, on the coasts of the Channel, of an old shore 

 line, now raised 10 to 30 feet above the level of the pre- 

 sent beach, those conditions are often present, the Old 

 Cliffs being generally masked and hidden by a mass of this 

 Rubble. The idea that it was a mere talus was soon aban- 

 doned, because the debris does not lie at the angle of repose 

 assumed by a talus, and because it contains blocks of stone 

 not belonging to the cliff, but that have come from beds 

 at some distance inland. Amongst the best examples of 

 the "iZt'afZ," as it has been termed, overlying the Raised 

 Beaches, are the masses of rubble exhibited in the cliff 

 immediately east of Brighton, and on the cliffs at Portland 

 ])ill, Hope's Nose near Torquay, and at Baggy Point near 

 Barnstaple. 



