124 M. Ch. Martins' Bemarks on J/. Durochefs Memoir 



to 1000. This ice, therefore, partly swims on water ; and if 

 a glacier supported its sides on the shore, that would be suf- 

 ficient to sustain it above a liquid mass. These consequences 

 are verified in nature. The glacier of Aletsch, in Switzer- 

 land, rests on the surface of Lake Mccrill ; all the glaciers 

 which occupy the bottom of the Spitzbergen bays, advance 

 above the sea, to a certain distance, supporting themselves 

 on the shores of the bay.* For all these reasons, it does not 

 appear to me absurd to suppose, that, by enlarging the pro- 

 portions of the phenomenon, the glaciers formerly crossed 

 the Gulf of Bothnia, as they have probably traversed the 

 lakes of Switzerland. In this country, we can demonstrate, 

 from the altitudinal limit of the ancient lateral moraines left 

 by these glaciers, that their base did not rest on the bottom 

 of the lake, but corresponded very nearly to the actual level 

 surface of the water. 



The portion of his map of the direction of the stride, which 

 M. Durocher has derived from that of M. Sefstrom,-|- pre- 

 sents, on the shores of the Gulf of Bothnia, between Gefie 

 and Oeregrund, arrows running from NE. to SW., as if 

 the grooving force advanced from the sea towards the inte- 

 rior of the country. From this M. Durocher draws a great 

 argument against glaciers, which, he says, cannot rise from 

 the bottom of a basin, like the Gulf of Bothnia, upon the shore. 



The objection applies equally to currents ; but I shall not 

 discuss it ; for I have strong reasons for thinking, that the 

 direction indicated by M. Sefstrom is not the mean direction, 

 but that he has been led into error by local deviations. The 

 recollections of my journey in 1839, in which I travelled 

 from Gefle to Upsal, crossing this region, recall nothing of 

 this nature. 



Such are the objections M. Durocher makes to the ancient 

 extension of the glaciers of Scandinavia. Not to prolong 

 the discussion, I shall not enter upon the enumeration of the 

 difficulties that may be raised against the hypothesis of dilu- 

 vial currents ; my task would be difficult from other causes, 



* See my observations on the glaciers of Spitzbergen, Bibliothcque Univcr- 

 $eUe de Geneve, t. xxviii.. p. 160. July 1818. 



t Annales de Physique de Toggendorff, t. xliii. 1838. 



