A Note Regarding the Present Status of the Iowan Drift Problem

Among the many persons who, by their publications, have made known to the world the Pleistocene history of Iowa, no one has had a greater part than Doctor Calvin, who spent his life endeavoring to interpret the geological phenomena of the slate. For many years, but chiefly from about 1895 until his death in 1911, important papers were written by him in the reports of the Iowa Geological Survey, of which he was Director, and in other channels of publication. None of these publications are of greater interest than those which describe the characteristics, relationships, and age of the Iowan drift