the figure of five hundred thousand years, as a minimum for Pliocene time, seem rather conservative. Toward the close of the Tertiary era the finishing touches were placed upon some of the greatest of the geological works. The folding of the strata, which had been going on for a long period in Eastern New York, was brought to an end by a violent rupture therein, and the out-rushing igneous rock, which was subsequently cooled rapidly by the floods of water flowing over it, gave us the beautiful palisades of the Hudson River. In the west, this folding resulted in the Rocky Mountains and the Coast Range, with their attendant high plateaux. In Europe, the Alps and the Pyrenees Mountains both belong to this period, while the grandest and highest of all mountain chains, the Himalayas, of Asia, were the culminating effect of the gigantic foldings of the earth's crust. The deposits of the Tertiary period will aggregate somewhat more than three thousand feet, and, inasmuch as this entire time was one of continued change in level, or the fluctuation between the subsidence of the earth's strata on the one hand and the elevation on the other (particularly in the Pliocene period), it is very hard to form any conjecture as to the actual amount of time required to do this work. Certainly, from what we know of the rate at which like phenomena are taking place at the present time in Northeastern North America, in Northwestern Europe, and Western Asia, the figure, as sometimes given, of ten million years seems very conservative.