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 100 nearly resemble ourselves; for these have rarely been recognised in a fossil state. Perhaps, however, we ought not to insist very strongly on either of these negations: for the quadrumana could not be expected to occur often in a fossil state far from the tropical forests which might shelter and feed them; and man only braves the cold of northern climates by his superior knowledge of nature, and inventions to meet its variations. These arts and that knowledge must be supposed of slow growth; and we may consistently believe that, though mankind at the diluvial era might not have extended to these far northern lands, where, only, the ossiferous caves and deposits have been adequately examined, human remains may yet be discovered in those warmer regions of the globe, which seem more congenial to the easy existence of our race, and have not yet been searched for the bones of our progenitors.

The supposed exceptions to this law of the absence of the remains of man from tertiary and diluvial accumulations (the bone caves of Bize, near Narbonne, the valley of the Elster, &c.) may be discussed hereafter: suffice it now to say that they are not thought sufficient to establish the affirmative of this important proposition. It appears, therefore, that we must look upon the existence of man and many races of animals which, more strictly than he, are appointed to live under particular physical conditions, as characteristic of the last of several great periods of geological time, each marked by the creation of peculiar races of plants on the land and animals in the sea.

From what we now see of the dependence of animal and vegetable life on climate, moisture, soil, and other characters of physical geography, there can be no doubt that to every system of organic life in the successive geological periods belonged certain combinations of physical conditions. These conditions were, indeed, not the cause of those systems of life; but both are to be looked upon as mutually adjusted phenomena,