28o 



PREHISTORIC EUROPE. 



On the same geological horizon as the ossiferous sands of 

 Eixdorf occur the freshwater sands of Tempelhof (Mark Bran- 

 denburg), which have yielded Paludina diluviana, Kth., Bithynia 

 tentaculata, L., Valvata piscinalis, Mull., and Pisiclium amnicum, 

 Mull. 



It was formerly supposed that only two boulder-clays occurred 

 in North Germany, which were ranged, along with associated 

 beds of clay, sand, and gravel, in two groups, termed respect- 

 ively Upper and Lower Diluvium ; but it is now known that 

 the lower boulder-clay which appears under the ossiferous beds 

 of Eixdorf and the freshwater shelly deposits of Tempelhof is 

 not the oldest till. In the neighbourhood of Potsdam it is 

 underlaid by an older set of freshwater deposits, which contain 

 the same species of shells as those at Tempelhof, with the addi- 

 tion of Succinea amphibia, while immediately underneath these 

 beds comes a third boulder-clay. That this last boulder-clay 

 may possibly represent the ground-moraine of more than one 

 ice-sheet is shown by a boring made near the Schwielow-See, 

 which, according to Berendt, gave the following results : — 



Metres. 



3-3. 



25. B. 



6-5. C. 



73. D. 



E. 



It is quite possible that the sand-beds B and D may represent 

 interglacial beds ; on the other hand they may be merely lenti- 



