To a naturalist nothing is indifferent; the humble moss that creeps upon the stone is equally interesting as the lofty pine which so beautifully adorns the valley or the mountain: but to a naturalist who is reading in the face of the rocks the annals of a former world, the mossy covering which obstructs his view, and renders indistinguishable the different species of stone, is no less than a serious subject of regret.
The past history of our globe must be explained by what can be seen to be happening now. No powers are to be employed that are not natural to the globe, no action to be admitted except those of which we know the principle.
