"an old bone yard." In digging other wells in this vicinity mammal bones have been taken up by the settlers from about the same horizon. It is to be regretted that, with one exception, none of these fossils have been preserved for study, for it is likely that they were the remains of animals which were killed in the dust shower.
In the absence of fossils definitely known to be connected with the ash, its exact age seems yet uncertain. In McPherson County it is underlaid by clay, gravel, and sand, which contain remains of the horse, of a megalonyx, and of bivalve mollusks of modern aspect. In the bluffs of the Missouri River near Omaha pockets of a similar ash rest on glacial clay under the loess. At the latter place it must belong to the Pleistocene age, and at the former it can not be older than the late Pleiocene. These two deposits may not belong to the same shower, but it appears, at any rate, that the volcanic disturbances which produced them occurred near the beginning of the Pleistocene age.
In comparison with the slow and even tenor of the routine of geological history, the event here sketched appears so unique and so striking that it may well be called a geological romance. Modern science has taught us that the geological forces are slow and largely uniform in their work, and that most of the earth's features must be explained without taking recourse to theories involving any violent revolutions or general terrestrial cataclysms. While the making of this dust is not any real exception to the law of uniformity, we are here reminded that Nature is quite independent in her ways, and that even in her sameness there is room for considerable diversity.