A number of archaeological sites, particularly in the northwestern part of the continent, have yielded smooth ovoid stones which look suitable in every way for use as hammerstones, but which show no signs of having been used. In excavating a site it is a common experience to come across one of these, thinking one has found an actual hammerstone, only to discover, after it has been washed, that it is merely an ovoid cobblestone. Yet it is quite clear that the stone is part of the archaeological series and not merely a stone lying in situ. So frequent are these in some sites that students on the dig have adopted the habit of calling them “unused” hammerstones.