586 STRATIGRAPHICAL GEOLOGY 



that the London, Hampshire, and Paris basins were formed and 

 separated from one another, and it is specially noticeable that the 

 sharpest flexures are along the southern sides of the Hampshire 

 and London basins. The well-known monocline of the Isles of 

 Wight and Purbeck is one of these flexures, and that of the Hog's 

 Back ridge west of Guildford is another. The general result was 

 to elevate the whole of Northern Europe into high ground on 

 which no large areas of deposition seem to have existed. 



After these disturbances there seems to have been a partial sub- 

 sidence ; the Atlantic Sea of Helvetian time invaded the west of 

 France, and occupied not only part of the Aquitanian area but also 

 that which is now the valley of the Loire, forming a gulf which 

 reached as far up as Blois. The sea also passed northward by 

 Rennes to Gahard and Dinan, so that the central and western parts 

 of Brittany were probably reduced to the condition of an island. 

 The Southern Sea also spread northward through Provence and 

 Dauphine to the Jura, and thence round the northern side of the 

 Alps to Austria, through parts of Bavaria to Bohemia and Poland, 

 and eastward through Galicia and across the south of Russia. 

 There must also have been some connection between the French or 

 Swiss gulfs and the Belgian Sea, though by what route has not yet 

 been definitely ascertained ; it is certain, however, that such shells 

 as Conus Dujardini, G. antediluvianus, and Terebra Basteroti must 

 have come from the south. 



The concluding phase of this period seems to have been pro- 

 duced by a general uplift of the southern region, which raised 

 parts of the Mediterranean area into dry land and led to the 

 formation of the shallow Sarmatian Sea, a large enclosed sea which 

 extended from the Danubian basin through the Pontic area to the 

 Caspian region, with a gulf that stretched southward into the 

 JSgean area. The two main basins of the Mediterranean seem also 

 to have been occupied by shallow seas which covered parts of 

 Italy and Sicily and reached westward to the neighbourhood of 

 Barcelona in Spain, where sands and marls with Oerithium pictum 

 and Mactra podolica are found, but the rest of Spain appears to 

 have been part of the Continental area, and the westward opening 

 of the Mediterranean into the Atlantic lay through Morocco. 



II. THE PLIOCENE' SERIES 



A. SUBDIVISIONS AND NOMENCLATURE 



In most parts of Europe the Pliocene deposits are of small 

 thickness and of no great extent, and were mostly accumulated in 



