CATSKILL (formerly Kaatskil) MOUNTAINS, a group of moderate elevation pertaining to the Alleghany Plateau, and not properly included in the Appalachian system of North America because they lack the internal structures and the general parallelism of topographic features which characterize the Appalachian ranges. The group contains many summits above 3000 ft. elevation and half a dozen approaching 4000, Slide Mountain (4205 ft.), and Hunter Mountain (4025 ft.), being the only ones exceeding that figure. The bottom lands along the creeks which drain the mountains, together with rolling uplands rising to elevations of from 1500 to 2000 ft., are under cultivation, the mountain slopes being forested or devoted to grazing. The pure and cool atmosphere attracts summer visitors, for whose accommodation many hotels have been built, some of which have become celebrated. Stoney Clove and Kaaterskill Clove are picturesque gorges, the former being traversed by a rail way, and the latter containing three cascades having a total fall of about 300 ft. The growing need of New York City for an increased water-supply has driven her engineers to the Catskills, where several great reservoirs have been projected to supplement those of the Croton watershed.