The Niagara River runs half its length on an upper plain, then drops at the falls into a narrow gorge through which it courses seven miles to the escarpment, the crest of which is a bed of limestone--60 ft. thick at the falls. The water plunges into a deep basin hollowed out of soft shale, which, as well as the escarpment, is being constantly worn away. The site of the cataract retreats upstream and the gorge is lengthened at a rate of about five ft. a year. It is evident that the whole gorge has been dug out by the river, and many attempts have been made to determine the time consumed in the work. The solution of the problem would aid in establishing a relation between the periods and ages of geologic time and the centuries of human chronology. The Horseshoe Fall wore its cliff back 335 ft. in about 63 years. Geologists have computed 25,000 years as a lower limit for plausible estimates of the river, but have been able to set no upper limit. The Canadian and American shores are connected by three bridges, one of which a suspension carrying all classes of traffic, is 1,240 ft. long. The flow of water in the river averages 222,000 cubic ft. per second, though it sometimes falls as low as 176,000 cubic ft. On March 29, 1848, Niagara ran dry, and persons walked in the rocky channel bed of the American Rapids between Goat Island and the mainland. This phenomenon, never known before or since, was due to these facts. Lake Erie was full of floating ice flowing to its outlet, the source of Niagara River. During the previous afternoon a heavy northeast wind had driven the ice back into the lake, and during the night the wind, suddenly veering, blew a gale from the west which forced the ice floe sharply into a mass in the narrow channel of the river, where it froze. Thus, when the water on the lower side of the barrier drained off, the Niagara River and the American Fall were dry, and the Canadian Fall a mere trickle. This extraordinary condition lasted for a whole day. Thus the descent of this stream at the Falls and in the Rapids just above them gives in theory a water-power of nearly 4,000,000 lip., three-fourths of which is estimated as available. This maximum could be obtained only by sacrificing the beauty of the Falls--in fact diverting the river from its channel so that the cataract as a scenic feature would be destroyed. To combat this commercial vandalism an association for the protection of the Falls has been formed. There were before 1918 several companies with power-producing plants, the largest of which was the Niagara Falls Hydraulic Power and Manufacturing Company. This company had made an extensive beginning in utilization of the water fall by a tunnel 29 ft. deep and 18 ft. wide, passing about 200 ft.. below the surface of the city from a point 1-1/4 M. above the Falls to the upper steel arch bridge.