220 On the Alpine Glacier, Iceberg, QNo. 159. 



tures in the distribution of Alpine glacial striae are thus diverging at 

 the outlets of the vallies, and their being oblique and never horizontal 

 on the flanks, which they would be, were they due to the agency of 

 water, or floating masses of ice. 



The cause of their obliquity M. Agassiz ascribes to the upward 

 expansion of the ice by the freezing of the water infiltered into the 

 crevices and pores of the glaciers, and the descending motion of the 

 glacier itself which he considers produced by this expansion of the 

 mass and its gravitation. 



From the resemblance in shape, and the interior arrangement of 

 the beds of the so-called diluvium of England, France and Germany, 

 that of the moraines confessedly produced by existing Alpine glaciers ; 

 from the presence on these rocks of furrows, &c. resembling those 

 now produced at the bottom of moving glaciers ; their radiation from 

 mountain centres of elevation and coincidence of direction with that 

 of the vallies down which glaciers would descend ; their obliquity just 

 described, and from the existence on the Jura limestone of basin and 

 funnel-shaped cavities, and small indentations similar to those 

 seen forming at the bottom of glaciers by small and temporary cas- 

 cades descending through cracks and chasms in the ice, and from the 

 association in those regions of these Alpine phenomena, which M. 

 Agassiz contends are inexplicable on any theory of aqueous action apart 

 from ice ; he infers, as already stated, that very large portions of the 

 now temperate regions of the globe have for a long period been covered 

 with ice and snow. 



A few shells of an arctic character, which have been found in the 

 boulder deposits of Scotland and North America in addition to the above, 

 constitute all the evidence we have of the period of intense cold, on 

 which rests the Alpine glacial theory as applicable to the boulder de- 

 posits ; and which M. Agassiz ingeniously imagines, accounts for the 

 extinction of the mammoths which flourished in the warm period 

 immediately antecedent, and the appearance of their frozen remains in 

 arctic glaciers. The frozen period was followed by the more temperate 

 human epoch. 



The views of M. Agassiz on the origin of the boulder deposit have 

 met with powerful support from Dr. Buckland, and partially from 

 Mr. Lyell. 



