Pere 
J, D. Dana on American Geological History. 327 
we know how the ice, while a glacier, or along a shore of cliffs, 
(for all bergs are believed to have once been glaciers,) may re- 
1 
uget’s 
Sound north, of Southern South America from Chiloe south, of 
elevation was in the period of the ciara He has not been pre- 
But as they are proof o 
the earlier, we have reason for referring the greater part of the 
, elevation to that Drift era, and for believing that the excavation 
| of these fiord valleys was then in progress. Both fiords and drift 
However this be, there is other evidence in the cold of the : 
iod, of some extraordinary cause of cold. The drift m 
