586 Surface Geology of Eastern Massachusetts. (October, 
ages long anterior to the Post-Tertiary ice time. Valleys must 
precede valley-eroding glaciers. 3 
From our remote northwestern coast we have yet more con- 
clusive testimony to the preglacial origin of the phenomena in 
question. In no region, save perhaps the western coast of Nor- 
way, is there a grander development of fiords than on the Pacific 
eoast of North America, from the labyrinth of Vancouver Isl- 
and northward. These fiords are cut in the seaward slope of a 
bold mountain range, bearing the lofty peaks of Fairweather 
and St. Elias. According to Mr. W. H. Dall, almost every fiord 
of considerable size on this coast, especially toward the north, 
“ has at its head a glacier, or the remains of one. Some of these 
glaciers are of extraordinary size and grandeur.” The same 
authority states that evidence is wholly wanting that these gla- 
ciers ever much exceeded their present limits. The walls of the 
fiords, short distances below the present terminations of the 
glaciers, are not smoothed or striated; and no terminal moraines 
stretch across the fiords, or form shoals at their mouths. These 
are typical fiords, and yet the evidence that they are not due to 
the action of ice in any recent geologic time is rendered conclu- 
sive by the occurrence in some of the fiords having glaciers at 
their sources, according to Mr. Dall, of islands composed of soft 
and yielding Tertiary strata, which must have been completely 
swept away had the ice streams ever filled the gorge. The ex- 
istence of these Tertiary beds is a certain indication that the 
fiords antedate that period, and hence they are, in a certain 
sense, the cause rather than the consequence of the present 1ce 
streams. 
The tendency of the considerations here presented is evidently 
toward the view that, comparatively speaking, the 1ce-cap 
rested lightly upon the land, and that the topographic features 
having a skeleton or frame-work of rock are, as a rule, of pre 
glacial origin. In other words, it appears probable that if on 
present mantle of drift were entirely removed from the face 0 
the country, leaving a surface of naked rock, we should have 12 
all important respects a restoration of the anteglacial contours: 
And this ancient topography having been, as I conceive, fashion | 
mainly by agents more subtle than an ice-cap, and hence taking 
a deeper hold on geologic structure, would if thus undisgu she 
reveal a closer correspondence with the structure lines nes 
subjacent rocks than we are able to detect in the existing 
and valleys considered as a whole. 
