Page:Popular Science Monthly Volume 55.djvu/345

Rh is not at all improbable; but how does this modernize the object, when the gravel extends quite to the surface? The pebbles and bowlders at the top of the bank are clearly as much a part of the deposit as are those at its base, and while the surface may be—is, in fact—less ancient than the deeper gravels, still they can not be dissociated; and it is a significant fact that we find, on the gravel at the foot of the bluff or other exposure, only the rude argillite objects at the water's edge or on the fiat laid bare at low tide, and not



a general assortment of the Indian's handiwork, including pottery; and we must not overlook the fact that the "gravel-bed" implements bear evidence of all the conditions to which the gravel itself has been subjected—this one stained by manganese, that incrusted with limonite; this fresh as the day it was chipped, because lost in sand and water and not subsequently exposed to the atmosphere; that buried and unearthed, rolled, scratched, and water-worn until much of its artificiality has disappeared. The history of almost every specimen is written upon it, and not one tells such a story as has been told about it by the advocates of the "Indian-reject" theory.

Much has been written on the natural history of the gravel that is so marked a feature of the river valley, particularly at the head