REVIEW OE OLD AND NEW STANDARDS OF PLEISTOCENE DIVISION 431 



Europe are also in perfect harmony with this classification of the Glacial 

 Period and of the fluvial terraces. 



Deperet's Correlation of northern Moraines and Mediterranean 



Quaternary Shorelines 



In the north of Europe there took place repeated invasions of great 

 sheets of land ice, spreading from the Scandinavian and Scottish moun- 

 tains, advancing and eroding the basins of the Irish, the North, and the 

 Baltic seas, and stretching out over the British Isles, the German plains, 

 and the plains of Poland and Eussia. The sea was excluded from these 

 basins by masses of ice many thousands of meters in thickness, and it 

 was only during intervals between glaciations that the sea was able to 

 return and form marine and interglacial deposits. The subsequent 

 return of the glaciers would cause erosion and the more or less complete 

 destruction of the marine deposits of the preceding interglacial phase. 

 Thus comparison with the undisturbed marine deposits of the Mediter- 

 ranean borders is rendered very difficult. Nevertheless, certain surviving 

 marine deposits of the north of Europe may be correlated with those 

 of the Mediterranean, as follows : 



1. Sicilian Stage of the Mediterranean = Cromerian Stage of the North Sea 

 characterized by species of the basin and Baltic, with its regres- 



north imported by cold Atlantic sive marine phase at the begin- 



currents (see above). ning (Forest Bed of Norfolk) and 



its transgressive terminal phase 

 (deep-water clays with Yoldia 

 myalls and arctica). Many arctic 

 species (187) imported by the 

 deep currents of the glacial ocean. 



1. Sicilian Stage, Deperet, 1920. — On the east coast of the Xorth Sea 

 and along the German-Baltic coast Deperet recognizes marine faunal 

 beds of Sicilian-Cromerian age, covering a ground moraine of (I) 

 Scanian-Giinzian age, so that they occupy an interglacial position. De- 

 peret (1920.1, 1920.2) similarly reviews the glacial and interglacial 

 deposits of Great Britain, and on the basis of the eustatic movements of 

 sealevel concludes : 



"The following table summarizes the coordination that I believe I shall be 

 able to propose between the Quaternary formations of the British Isles and 

 those of the Mediterranean. If this coordination is accepted, the whole Qua- 

 ternary history of the British Isles may be explained without being obliged to 

 invoke the least movement of the earth, either epirogenic or even isostatic." 



