OSBORN. REVIEW OF THE PLEISTOCENE 231 



are of later date than the marine Pliocene deposits of southern Europe. 

 Before any of these glacial deposits occurred there was an elevation of 

 the marine Pliocene strata along the southern Alpine borders from sea 

 level to a height of from 300-500m. ; there also occurred erosion of these 

 marine strata by rivers. Thus in the valley of the Po there is a consid- 

 erable time interval between the closing marine conditions of the Plio- 

 cene and the opening Pleistocene conditions. In the valley of the Khone 

 also there is a marked interruption between the strata of the Pliocene and 

 of the Glacial epochs, the latter overlying the strata recognized as Upper 

 Pliocene, which in turn overlie the marine Pliocene. 17 



This interval between the Pliocene and Pleistocene corresponds with 

 very important changes which occur in the mammalian life of Europe, 

 namely, in the extinction of many characteristic Pliocene mammals, such 

 as the anthropoid apes, the antelopes and the mastodons. 



z o „ £ « g U 

 1 I 2 § gg2 



o X tt i q_ fcq 



Sierra de Credos Alps Mis 



Mas Mts I Pyrenees Mtz. I 



Germany Scandinavian Plateau 



jlJ'T* | | North Cape 



North SKgger 

 Sea Rak 



PROFILE OF PAST AND PRESENT SNOWLINES AND CLACIERS OF EUROPE 

 Fig. 4. — Theoretic snow levels during the Glacial Epoch 



Prepared under the direction of the author by Chester A. Reeds from data given hy 

 J. Geikie, Penck, Briichner, Leverett and Stieler's Hand-Atlas, December, 1914. 



The traces of four different glacial advances and retreats observed 

 around the northern slopes of the Alps by Penck and Bruckner 18 were fol- 

 lowed with their "river drifts" and moraines down the Danube to the 

 neighborhood of Vienna; they were found to be clearly marked in the re- 

 gion of the upper Ehine and of the Rhone around Lyons, and distin- 

 guishable both by the greater or the less extension of their borders and by 

 the greater or less erosion which has occurred in the intervals between 

 their successive depositions. These four advances were named respec- 

 tively the Griinz, the Mind el, the Ptiss and the Wiirm. 



As an instance of the disparity between the duration of these several 

 glacial advances with the accompanying descent of the ice and snow line, 

 the old moraines of the Eiss or third glaciation form a girdle around the 

 more recent Wiirm or fourth glaciation, proving that the Eiss was not 



17 Op. cit., pp. 654-655. 

 ie Op. cit., p. 47. 



