122 M. Ch. Martins' Remarks on M, Durocher's Memoir 



present. In fact, it is necessary, in order that glaciers might 

 slide along the bottom of the sea, that its temperature should 

 be constantly below zero ; for, if the temperature of the latter 

 were maintained above the freezing point during several 

 months of the year only, the glacier would float upon the sur- 

 face of the sea, and not striate its bottom. I think that I 

 have established this point in my observations on the glaciers 

 of Spitzbergen.* During the glacial epoch, it is, therefore, 

 probable that the coast was higher than at present, for we 

 must suppose it to have been more elevated before all the 

 striae could be submerged. But since it has undergone re- 

 markable oscillations, as is proved by the balani of Udevalla, 

 seen by M. Brongniart,t 60 metres above the sea ; the ser- 

 pulse fixed on polished rocks between Christiania and Aggers- 

 bach;! and above all, by the bed of clay and shells {Ska- 

 lenschicht) described by M. Keilhau, and which are found to 

 the height of 188 metres above the sea, and 12 myriametres 

 from the coast.§ The oscillation of the coast of the penin- 

 sula is, therefore, a fact mathematically demonstrated. Let 

 us now see whether the portion of the Norwegian coast, of 

 which M. Durocher speaks, presents any marks of these 

 changes of level. Areskutan is situate under the same lati- 

 tude as Drontheim, but 10 myriametres into the interior of 

 the country. Now, in the Beistadfiord, 11 myriametres to 

 the north of Drontheim and Areskutan, M. de Buch|| found, 

 at a height of 140 metres, marine shells, which he considers 

 the same as those of the deposit near Drammen, the greater 

 part of them now living in the North Seas. These are, My- 

 tilus edulis, Cardium eduli, Mya truncata^ Venus Islandlca, 



* Bibliotheque Universelle de Geneve, July 1849; Bulletin de la Societe 

 Geologique, Meeting of 4th May 1840; and Edin. New Philosophical Journal, 

 vol. XXX., p. 284, 1841. 



t Notice of the blocks of rocks found in transported formations, Annates des 

 Sciences Naturelles, t. xiv., 1828. 



J Scheerer, Beytraege zur Kentniss des Seftstroem'schen Frictions Phenomen., 

 Annales de Physique de Poggendorjf, 3d series, t. vi,, 1844. 



§ Daubrec, Note on the Erratic Phenomena of the North of Europe. Bul- 

 letin de la Societe Geologique, t. xiv., p. 574, 19th June 1843. 

 II Reise durch Norwegen und Lappland, t. i., 251. 



