Fjords and Hanging Valleys. — Upbam. 313 
landward continuations of their valleys, show a perfect analo- 
gy with river systems. Therefore Dana, a half century 
ago, in 1855, in his address as the retiring president of the Am- 
erican Association, explained the fjords as channels eroded 
by rivers when the lands so indented stood higher than now, 
at altitudes measured by the depths of the fjords now beneath 
the sea ; and at the same time he sagaciously ascribed the 
cold of the Glacial period to such increase in the elevation and 
extent of northiem lands. 
An argument lately urged against the river-erosion of the 
fjords, and instead, referring these deep, narrow, and often 
irregularly bending, zigzagging and branching valleys, chan- 
neled far beneath the level of the sea, to ice-erosion, is drawn 
from the frequently discordant junctions of their ' relatively 
small tributaries. On each side of the deep fjords, and in like 
manner on the sides of deep inland valleys of glaciated areas, 
the small inflowing streams often occupy mature upland val- 
leys, which have gentle descent until near or at their de- 
bouchure into the main valley, where they suddenly fall oft' 
hundreds of feet to join the trunk valley or bed of the fjord. 
These high tributary' stream courses, having so remarkable 
discordance, have been called hanging valleys by Gilbert and 
Davis ; and other geologists and geographers have generally 
adopted this name for these significant topographic forms. It 
is argued by Gannett.* Gilbert.f Davis.i Hubbard, § and oth- 
ers, that glaciation of the main valley or fjord cut it down so 
far beneath its former land surface, while the small tributary 
valleys were only slightly lowered by the feebler glaciation 
there, the ice being thinner and having slower motion. 
But against this theory of glacial erosion of great valleys 
and fjords beneath the levels of the small hanging valleys, 
strong reaction and remonstrances have yet more recently 
♦Henry Gannett, "Lake Chelan," National Geographic Magazine, vol. ix, 
pp. 417-428, 1898. 
tG. K. Gilbert, "Glaciers and Glaciation," Harriman Alaska Expedition, 
vol. ill, 1904. 
tW. M. Davis, "Glacial Erosion in France, Switzerland, and Norway." 
Proceedings of the Boston Society of Natural History, vol. xxix. pp. 273-322, 
July, 1900. This paper contains a bibliography in its hist two pages : and 
It notes the first use of the name hanging vaUeya, as proposed in 1899 bv 
Gilbert, on page 288. 
§George D. Hubbard. "Fiords." and "On the Origin of Fiords," Bulletin 
of the American Geographical Society of New York. vol. xxxlll. pp. 330-337, 
and 401-408, 1901. (Prepared as a thesis in Geography, under Prof. W. M. 
Davis, at Harvard University.) 
