Evidences of Epeirogenic Movements.—U pham. 105 
thus noted, for the greater part or nearly all of this difference 
in depth. 
Glacial erosion, which contributed the latest part in the 
sculpturing of the fjords, also tended to the same result; but 
I think that this element of their origin was secondary to river 
action and far less efficient. The tributary drainage courses 
opening at great hights upon the sides of the fjords, called 
“hanging valleys” by Gilbert and regarded by him and by 
_ Davis as proofs of mainly glacial erosion of the grand fjords, 
may be attributed in some places to changes of the preglacial 
topography by glaciation and drift deposits, carrying post- 
glacial streams where none before existed. It is very difficult 
to suppose that the greater part of the channeling of the fjords 
of Norway took place during the glaciation of the country, by 
ice erosion, as would be required by the argument from trib- 
utary “hanging valleys,” entering the great fjords by high 
waterfalls. According to that explanation, the masses of 
morainal drift at the mouths of the fjords along the outer coast 
would be of mountain size. More probably the fjord erosion 
in Norway was chiefly accomplished by rivers during the long 
Mesozoic and Tertiary eras, the stream beds being finally 
worn nearly or quite to the bottoms of the present fjords at the 
time of culmination of the pre-glacial and Early Glacial land 
elevation. The ensuing ice sculpture and drift accumulations 
gave the superficial and minor features of the landscape, but 
not its grand outlines. The great depths of the Norwegian 
fjords seem to me due mostly to preglacial stream cutting; 
but these very deep main river valleys were widened by 
glaciation from V to U forms of cross sections, the tributary 
valleys being thus truncated with precipitous falls.* 
Stages in the depression of this part of the earth crust 
from its great preglacial elevation are cited by dredgings from 
originally littoral shell banks at depths of 100 to 300 meters 
along the west coast of Norway, southwest of Ireland, near 
Rockall, and off the Fzr6e islands. 
* Consult recent papers by Pror. EDWARD HULL on the fjords and sub- 
merged valleys of Europe and Africa, Journal of the Victoria Institute, Lon- 
don, vols, xxx-xxxiii, 1898-1901; and by Pror. W. M. Davis, on Glacial 
Erosion in France, Switzerland and Norway, Proc., Boston Soc. Nat. Hist., 
vol. xxix, pp. 273-322, with plates, July, 1900, giving the bibliography of the 
theury of fjord erosion by glaciation. 
