OF WESTERN EUROPE AND THE MEDITERRANEAN COASTS. 919 
evidence less conclusive. This may be partly due to the fact that the coasts on the 
Bay of Biscay and of Portugal being more exposed to the severe westerly gales, 
the old beaches have generally been destroyed, and remnants only of detrital head or 
Rubble-drift left. 
The Coast south of Brittani/. —In the Island of Noirmoutier,^ on the coast of 
La Vendee, the “ Quartzite du Cobe” forms a low cliff, 15 to 20 feet high, against 
which abuts what from description seems to be a mass of angular rubble-drift rising 
to the height of 10 to 25 feet above the sea-level, but without a Raised Beach. On 
the coast between Biarritz and St. Jean de Luz, I saw no Raised Beaches, though at 
places there are traces of a Rubble-drift. This is well marked at the entrance of the 
valley at Bidart, where it forms a slope of angular debris derived from the local 
strata and from the plateau gravel. There is another section at the mouth of a small 
river south of Bidart where the debris forms a thick roughly stratified mass of gravel 
and loam (or Loess) inclined on the hill side. 
The evidence, though slight, is sufficient to show that on the south-western coasts 
of France, the Ptubble-drift is present, thereby indicating the operation of the same 
common cause which affected the coasts of the Channel. More striking evidence, 
however, to the same effect, but of a different class, exists in the interior of the 
country, and on the south coast, some of which we will now describe. 
Inland Forms of the Rubble-drift in France and Belgium. 
These embrace, 1st, the high-level or plateau Loess; 2nd, the angular drift or 
breccia on slopes; and 3rd, the ossiferous fissures. 
The Loess. —Few questions in Quaternary Geology have given rise to more frequent 
discussion than the origin of the Loess.t It was suggestively considered by Lyell,;}; 
and a critical review of the various opinions concerning it has been given by Professor 
James Geikie.§ The more general expressions of Continental opinion will be found 
in the works of M.M. De LapparentH and Credner,1I and others. Here we need 
only consider its origin, and must refer for details to the original memoirs. 
There is a general agreement amongst geologists that the Loess of the great river 
valleys is, up to the height to which the old rivers rose, due to floods connected with 
the melting of the ice and snow of the Glacial period. The Loess, however, is not 
* ‘Mem. Soc. Geol. de France,’ vol. 1, p. 325. 
t M. D’Archiac has given an excellent summary up to the year 1848 in his ‘Histoire des Progres de 
la Geologic,’ vol. 2, chaplers iii.-vi. 
+ ‘Antiquity of Man,’ 4th edit., chapter xvi. 
§ ‘ Prehistoric Europe,’ chapters ix. and xi. 
11 ‘ Traite de Geologic,’ p. 1084. 
T[ ‘Traite de Geologic et de Paleontologie,’ French Translation, pp. 6.39-641. 
