22 THE CANADIAN NATURALIST. [Feb. 



agency, my opinion was that these blocks were rather transported 

 to their present habitats on the Jura on ice-rafts, which were floated 

 away in water to the n.n.w., when the great glaciers melted, and 

 the low countries were flooded. I founded this opinion on the fact, 

 that in examining the Canton de Vaud, and particularly the tracts 

 near Lausanne and the north side of the lake of Geneva, I never 

 could detect the trace of true moraines. In that detritus I saw 

 merely accumulations of loose materials, which had all the aspect 

 of having been accumulated under running waters. But, even grant- 

 ing to the land-glacialists their full demand, and supposing that a 

 gigantic glacier was formerly spread out in fan-shape, as laid down 

 by several geologists, and recently in the little map of Sir Charles 

 Lyell, in his work on the Antiquity of Man, and that it became 

 eventually of such enormous thickness as to have carried up the 

 great blocks on its surface, to lodge them on the Jura Mountains; 

 there is still in it nothing which supports the opinion, as indeed 

 Sir Charles has himself observed,* that the deep cavity in which 

 the lake lies was excavated by ice. 



The geologists who first embraced the view of the transport of 

 the huge blocks on the Jura by a solid glacier, were of opinion that 

 the great depressions and irregularities of the surface which we 

 now see between the Alps and the Jura, including the lakes of 

 Geneva and Neufchatel, were so filled up with snow and ice, that 

 the advancing glaciers travelled on them as bridges of ice, the 

 foundations of which occupied the cavities. 



Let us now turn to the south side of the Alps, where a long incline 

 accounts for the enormous extension of glaciers into the plains of 

 Italy. Thus, in examining the remains of the old glaciers which 

 once advanced into the valley of the Po, MM. Martins and Gas- 

 taldi show us, that one of these bodies extended from Mount Tabor 

 to Rivoli, a length of fifty miles ; and, therefore, was longer than 

 any existing glacier described on the flanks of the Himalayas ; f 

 whilst those to the south of the Lago di Garda are shown to have 

 had a much greater length. Demonstrating, along with many 

 other authors, how these old glaciers had striated and polished the 

 hard rocks through or on which they had advanced, these authors 

 also clearly pointed out how the course of the glaciers had been 

 deflected, so as to take a new direction, when they met with the 



* See 'Antiquity of Man,' p. 312. 

 f Bull. Soc. Geol. de France, 1850. 



