Oh. XL] CONTINENTAL ICE OF GREENLAND. 14.3 



muddy water rushing from the Alps, has long been exploded ; and 

 the hypothesis of the submergence of Switzerland beneath the waters 

 of the sea, and the transportation of moraines and erratic blocks on 

 ice-rafts or floating icebergs from the Alps to the Jura, then an island 

 — a view to which I myself formerly leaned — has been disproved by 

 a careful study of the present distribution of the travelled masses. 

 Their arrangement, both on the north and south of the great chain, 

 whether in the Pays de Vaud and Jura or in the plains of the Po, is 

 such as to imply that they were transported to their present sites by 

 glaciers of enormous size descending by the existing valleys at a time 

 when all the great lakes were filled with ice, or, in other words, formed 

 parts of these same glaciers. The entire absence of marine shells 

 from the old glacial drift of Switzerland, and of the Alps generally, is 

 confirmatory of this theory, and against the doctrine of a marine sub- 

 mergence. The moraine-like arrangement of the boulders has also led 

 the most experienced Swiss and Italian geologists, who have of late 

 years devoted much time and talent to the study of this subject, to 

 adopt the same hypothesis of land-glaciers. Among other writers I 

 may mention MM. Studer, Guyot, Escher von der Linth, Morlot, Gas- 

 taldi, Gabriel de Mortillet, Omboni, and others. 



It has been stated that the boulder formation and all the attendant 

 phenomena of striated and dome-shaped rocks and far-transported 

 erratics become more and more conspicuous in proportion as we ex- 

 tend our survey to higher latitudes. We find, for example, a charac- 

 teristic display of them in Norway, Sweden, and Denmark, the south- 

 ern borders of the Baltic or Northern Germany, European Russia, 

 and Finland. They are also observable in the mountainous regions 

 of Scotland, Wales, and of the British Isles generally. But, besides 

 the appearances already noticed, there occur here and there in the 

 countries just alluded to, deposits of marine fossil shells, strictly be- 

 longing to the glacial period, which exhibit so arctic a character that 

 they must have led the geologist to infer the former prevalence of a 

 much colder climate, even had he not encountered so many accompany- 

 ing signs of ice-action. The same marine shells demonstrate the sub- 

 mergence of large areas in Scandinavia and the British Isles, and 

 other regions, during pails of the glacial epoch. 



A characteristic feature of the deposits under consideration in all 

 these countries is the occurrence of large erratic blocks and sometimes 

 of moraine matter, in situations remote from lofty mountains, and sep- 

 arated from the nearest points where the parent rocks appear at the 

 surface by great intervening valleys, or arms of the sea. Such appear- 

 ances require us to suppose important geographical changes of a date 

 subsequent to the drift. But even where the land does not seem to 

 have undergone much local alteration, such as would result from up- 

 heaval and subsidence, we often observe strise and furrows, as in Nor- 

 way, Sweden, and Scotland, which are not in strict accordance with 

 the direction of any separate glaciers, which can be supposed to have 



