The water power generated by the rapid descent of the streams in the part of the state lying north of the Fall Line has long been utilized for manufacturing purposes, and mills are found along all the streams in this part of the state. The location of Paterson as a manufacturing center is due to the water power developed from the Passaic Falls. At Trenton, water power is secured from the rapids of the Delaware River. In the northern part of the state, several streams and lakes are used to provide electric power and light. Closely connected with drainage systems and dependent largely upon them are the methods of supplying water to the people of towns and cities for domestic purposes. Formerly water for such purposes was obtained from near-by springs, wells, and streams. As population increased, the local sources of water supply became contaminated and dangerous to health. This danger and the larger quantity of water required by the increased population and by manufacturing interests have forced the larger cities to make provision for securing their water supply from sources, more or less remote, which are not subject to pollution. Their water-supply systems include pumping stations, reservoirs for storage, and long pipe lines. The drainage basins from which water is taken for municipal purposes are located in the thinly populated parts of the state. The northern mountainous section, which is not specially profitable for agriculture and other purposes, is particularly useful in furnishing sources of water supply. The many large cities in the northern part of the state draw their water from the upper parts of the Hackensack, Passaic, and Raritan basins. Formerly Newark and Jersey City drew their water from the Passaic River not far above the former city. This river was gradually so polluted by the sewage and the waste of factories discharged into it, that it had to be abandoned as a source of supply. These cities now bring their water long distances, Newark using the Pequannock basin, and Jersey City the Rockaway. In some cases water is obtained from artesian wells. The pollution of streams by city sewers and drains from factories destroys fish in fresh-water streams. The damage extends even into tidal waters, and many oyster and clam fisheries in the bays have been abandoned. The state is alive to the necessity of protecting its streams against contamination of all kinds and has enacted legislation designed to maintain their purity by preventing the flow of sewage and other objectionable matter into them. It has provided for the construction of a trunk-line sewer along the valley of the Passaic from Paterson to the sea, into which the sewers of the cities along its course will be discharged. In cooperation with Pennsylvania the state has passed laws to prevent the pollution of the Delaware River. PLANTS AND ANIMALS