EVIDENCE OF CHANGE OF LEVEL. 677 
map of Northwest America, Maine, Tierra del Fuego, and Norway. 
We also may often trace the gradual increase of this submergence as 
we pass from the more even coasts near the equator to these broken 
regions. On the northwest coast of America, the mass of islands, from 
Vancouver’s north, appear like the proper continuation of the coast. 
At the Straits of De Fuca commences this narrowing of the continent, 
and the separation of Vancouver’s Island from the main is an obvious 
result of the submergence. Along New England, the coast gradually 
increases in its broken character from Rhode Island to the north. 
We would not be understood as saying that all these flords occupy 
valleys of denudation ; for some may evidently be the site of valleys 
of other kinds. Yet that many are of this character is evident from 
the existing valleys in the same countries. The absence of fiords, also, 
is not necessary evidence that a coast has not partaken in the submer- 
gence; for their formation, in such a case, depends on the topogra- 
phical character of the country submerged, and also, to some extent, on 
the enduring nature of its rocks. 
The inquiry still remains, whether the valleys of denudation, which 
have become fiords by submergence, have been excavated by running 
water alone, or more or less by glaciers. The greater elevation of the 
country, previous to this submergence, would undoubtedly render it 
more favourable than at present for glacier phenomena. The question 
is one that actual examination must determine. 
These evidences of submergence prove that a change of level has 
taken place on our globe which has similarly affected many regions 
north of the parallel of forty-five or fifty, while south of this latitude, 
this change was experienced, if at all, to a less and less degree, as we 
approach the tropics. It indicates the probable subsidence of the sur- 
face of our earth towards the higher latitudes, while about the equator, 
if there has been any corresponding change, it has been an elevation. 
Perhaps it is for this reason, that the great chain of America is highest 
in the equatorial regions, and diminishes in altitude towards either 
pole. It may be for the same reason, that both continents narrow so 
rapidly to the southward, and finally yield place to the ocean ; and a 
somewhat similar effect is apparent on the north. 
The period of this submergence, we do not attempt to indicate. 
The land was formerly much above its present elevation, and for a 
period long enough for the valleys to have been formed. Neither 
would we imply that the submergence is still in progress; for these 
regions, in some parts, give evidence of subsequent elevation. It may 
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