1893.] 



Submergence of Western Europe, $-c. 



81 



marine remains, nor does it exhibit any traces of glacial action. Its 

 component materials are always derived from the adjacent hills, and 

 none from a distance, so that they have undergone little or no wear, 

 whilst the only organic remains are those only of land animals and of 

 land shells. While possessing these characters in common, this drift, 

 to which the author gives the general term of " Rabble-drift," assumes 

 a variety of forms or phases. Another peculiarity of this drift is 

 that it is dispersed from many centres in a manner such as would 

 result, on the hypothesis of the late Mr. W. Hopkins, of Cambridge, 

 from divergent currents, if a considerable area at the bottom of the 

 sea were elevated at a given rate, and under certain depths of water. 



Some forms of this drift, especially the one overlying the Raised 

 Beaches of the Channel, have long attracted attention. The origin of 

 that unstratified rubble has been attributed to, 1st, an excessive rain- 

 fall and great cold ; 2nd, snow and ice slides on slopes ; 3rd, waves of 

 translation ; 4th, flood and fluviatile action during a period of great 

 cold. The author has already stated the objections that occur to 

 him to these several explanations, some of which no doubt meet 

 certain of the required conditions, but none of them embrace the 

 whole, and they all involve consequences incompatible with the 

 other phenomena. They all also depend on agencies that involve 

 an amount of friction and weathering which is conspicuously want- 

 ing in the Rubble-drift. There is the further objection that this drift 

 often exhibits results due to a force of propulsion for which the sug- 

 gested causes are manifestly inadequate. 



The object of this memoir is to show that there is evidence of drift 

 beds having the same origin extending over Western Europe and the 

 coasts of the Mediterranean. In generalising phenomena so widely 

 spread, the author has to depend to a great extent on other observa- 

 tions than his own. Owing to their number, only the more prominent 

 cases have been selected, and only such particulars can be given as 

 will serve to prove that, howsoever they may differ in detail, they all 

 point to a common cause and agree in showing that all are explicable 

 on the hypothesis proposed by the author, namely, of the submerg- 

 ence of the land concurrent with a subsequent upheaval. 



France. — On the coast at Sangatte, near Cape Blanc-Nez, the 

 Rubble- drift, which assumes the form termed " head " by Sir H. de la 

 Beche, overlies a raised beach, the section being in almost every 

 respect identical with that at Brighton. The rubble is derived from 

 the adjacent Chalk and Pliocene strata, and has, as at Brighton, the 

 appearance of having'been shot over the old cliff in lenticular masses 

 — the most massive and prolonged being the one projected on the top. 

 This rubble contains the remains of Mammoth and some entire land 

 shells. Near Abbeville, a very similar drift about 40 feet thick follows 

 the slope of the hill, but here it forms four divisions corresponding 



VOL. liii. G 



