472 PREHISTORIC EUROPE. 



clay. Followed up from the maritime districts into the interior 

 of the country, this deposit of clay is found to be continuous 

 with lacustrine beds — accumulations of freshwater origin. At 

 the lower levels of the land it is thicker and purer than in the 

 inland districts, where it frequently contains layers and beds of 

 fine sand. It is often covered by deposits of sandy clay and 

 sand, in which boulders and erratics occur not unfrequently, 

 especially towards the top of the series. In Sweden, likewise, 

 the postglacial shelly clays are overlaid by a deposit of un- 

 fossiliferous sand (mosand), which covers as an almost con- 

 tinuous sheet wide areas in the low grounds. 



Erratics also are often found perched upon the tops of the 

 shell-banks or sprinkled over the surface of the shelly clays. 

 Lyell has referred to the occurrence of some large masses of 

 gneiss, 9 to 16 feet in diameter, which he observed resting upon 

 one of the postglacial shell -banks in the neighbourhood of 

 Upsala, and which seem to have impressed him as somewhat 

 remarkable. He says, " Here we have proof that the transport 

 of erratics continued to take place, not merely when the sea 

 was inhabited by the existing testacea, but when the north of 

 Europe had already assumed that remarkable feature of its 

 physical geography which separates the Baltic from the North 

 Sea." 1 We must not forget, however, that even in our own 

 day erratics are transported by floating -ice in the Baltic, 2 so 

 that the contrast between the present conditions and those that 

 obtained at the time the Upsala erratics were dropped or 

 stranded, is not so great as it might appear. 3 



From the facts which have been thus briefly summarised 

 we gather that in postglacial times the southern part of the 

 Scandinavian peninsula was submerged to the extent of 400 or 



1 Antiquity of Man, p. 281. 



2 Untersuchungen iiber die Erscheinungen der Glacialformation in Estland 

 und auf Oesel, Bull, de V Acad. Imp. des Sciences de St. Pitersbourg, vol. viii. 



3 For descriptions of Scandinavian postglacial deposits, see Professor Erd- 

 mann's Expose des Formations Quaternaries de la Suede, and papers by Professors 

 Kjerulf and Sars in Universitets-program (Christiania) for 1860 ; by Sars, Op. cit. 

 for 1864 ; by Kjerulf, Op. cit. for 1870 ; and, by same author, Udsigt over det sydlige 

 Norges Geologi, 1879. 



