The progress of research since Cuvier's time has supplied far more
striking examples of the long duration of specific forms of life than
those which are furnished by the mummified Ibises and Crocodiles of
Egypt. A remarkable case is to be found in your own country, in the
neighbourhood of the falls of Niagara. In the immediate vicinity of the
whirlpool, and again upon Goat Island, in the superficial deposits which
cover the surface of the rocky subsoil in those regions, there are found
remains of animals in perfect preservation, and among them, shells
belonging to exactly the same species as those which at present inhabit
the still waters of Lake Erie. It is evident, from the structure of the
country, that these animal remains were deposited in the beds in which
they occur at a time when the lake extended over the region in which
they are found. This involves the conclusion that they lived and died
before the falls had cut their way back through the gorge of Niagara;
and, indeed, it has been determined that, when these animals lived, the
falls of Niagara must have been at least six miles further down the
river than they are at present. Many computations have been made of the
rate at which the falls are thus cutting their way back.
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