on the Erratic Phenomena of Seandinavia. 123 



&G. A little to the south of Drontheim, at the entry of the 

 Joergenfiord, latitude 62° 20', M. Keilhau* observed terraces 

 rising 200 metres above the ocean. Thus, then, the coast of 

 Drontheim. which corresponds to the mountain Areskutan, 

 has been subject, like the rest, to considerable oscillation, 

 and wo cannot infer, from its present height, what was its 

 elevation at the period when the stria) were produced. 



The difficulty started by M. Purocher is not, therefore, 

 without a solution, and all his calculations on the ascending 

 motions of a glacier are without foundation, since it is all 

 but demonstrated that, at the glacial era, the relative levels 

 of the sea, the coast, and the interior of the country, were 

 not the same as now. It remains to be determined, whether 

 the mean direction of the striaa is really that which he de- 

 scribes; for I must observe that M. Siljestroem, who visited 

 this locality before M. Durocher, mentions only stri9B,t di- 

 rected from north to south, and others from east to west ; 

 and none of those running from I'W. to TE., on which M. 

 Durocher founds his reasoning. 



M. Durocher' s fourth difficulty is one of a similar nature. 

 He cannot comprehend how a glacier could cross obliquely 

 the deep depression of the Gulf of Bothnia, and then ascend 

 the hills of Finland. I can still less understand how a cur- 

 rent could do this ; in fact, a current from the N W. towards 

 this gulf, would have evidently deviated on entering this de- 

 pression, and would have followed its direction, which is 

 from NE. to SW., in the same manner as a river which 

 enters a valley, immediately takes the direction of that val- 

 ley. But we may conceive, how a mass of ice could traverse 

 a depression obliquely. The glaciers of Switzerland present 

 us with numerous examples. We must remember, that the 

 maximum specific gravity of the ice of glaciers is, according 

 to M. Dollfus' experiments, to that of pure water as 909 is 

 to 1000, a proportion which, with muddy water becomes 883 



* Nyt Magazin fur Naturviderskaberne, 1837, p. 220; and Bravais, On the 

 Lines of the Ancient Level of the Sea in Finraark. Voyages du Commission du 

 Nord en Scandinavia. Geographic Physique^ t. i., p. 117. 



t Carte do la Scandinavie, par AL Bravais. Atlaa des Voyage* de la Com', 

 mission du Nord. 



