feet, but the two ends, more than two thirds of the whole, are but natural embankments artfully rendered subservient to the purpose of the beaver by filling in between.
Fig. 2.—Beaver Dam.
It is these dams that produce those fine tracts of wild grass known as beaver-meadows, upon which cattle and deer so love to feed, and which so frequently furnish the pioneer with the means of subsistence for his stock until he can prepare meadows of his own. Wherever a brook trickled through a wooded valley, there the beaver made his home. Large areas became inundated, the drowned trees fell and decayed, and the freshets brought down new soil from the surrounding hills and ridges. At length the pond filled up and forced the beaver to migrate; the dam unrepaired gradually became shaky and the waters drained off, exposing a rich alluvial soil upon which sprang up waving fields of wild grass. In due time a second growth of timber appeared, and what was once a pond and valley became only a forest bordered by low ridges. In the suburbs of the city of Port Huron, Michigan, may be traced the remains of such a dam, of unknown age and stupendous length. Serpentine in windings, its face may be fol-
