SUPERFICIAL DEPOSITS. 223 



fragments of granite, syenite, schist, diorite, porphyry, slate 

 and conglomerate. The plutonic rocks may have come from 

 Cornwall, the Channel Islands or Brittany, and all of them 

 must have travelled long distances. 



In the north of France the diluvium seems to be the 

 equivalent of our clay. 



Bonnissent describes it in the departement de la Manche,* 

 where it contains angular and rounded fragments of neigh- 

 bouring and underlying rocks, as well as the remains of extinct 

 quarternary mammalia. The stones have sometimes been 

 carried some kilometres. 



Dupont,f in describing the superficial geology of the 

 neighbourhood of Dinant, in Belgium, gives the following 

 section : — 



1. Depots actuels, tourbes, eboulis, etc. 



2. Limon homogene, ou terre-a-briques. 



3. Depot a cailloux anguleux. 



4. Limon stratifie, ou fluvial. 



5. Depot a cailloux roules. 



The depot a cailloux anguleux consists of loamy clay, con- 

 taining numerous angular fragments of neighbouring rocks, 

 and this, together with the brick earth above, forms a deposit 

 very like our yellow clay. It is apparently, however, of later 

 date than the rubble drift of England, or the diluvium of 

 northern France, for it has only yielded the remains of the 

 reindeer, chamois, deer and horse. The depot a cailloux roules 

 below contains, like the rubble drift, the bones of the extinct 

 mammalia. 



PrestwichJ has described the occurrence of rubble drift 

 not only in England, France and Belgium, but also on the 

 coasts of Spain, Portugal, Malta, Greece, Crete, Turkey, &c. 

 Where raised beaches occur in these localities they underlie 

 the drift, as they do further north. It appears to be some- 

 what open to question, however, whether all the deposits he 

 mentions are really homologous, and can be accepted as true 

 equivalents of each other. 



Quarternary geology is full of unsolved problems and 

 unsettled questions, and no part of it has given rise to so much 

 discussion and to so many conflicting theories as the super- 

 ficial deposits south of the glaciated area. So far as concerns 

 these deposits in the Channel Islands, we have, to begin with, 

 clear and conclusive evidence that Jersey and Guernsey were 



* " Essaie Geologique sur le Departement de la Manche," p. 377. 

 t ''L'hornme pendant les ages de la Pierre." 



X " On the Evidences of a Submergence of Western Europe, &c." Phil. Trans., 

 Vol. II., 1893, p. 917. 



