The Chautauqua basin, since the era of ice, has been covered 



with great beds of northern drift which are deep, even upon the hills, 

 but lie deepest in the valleys. Before the glaciers came to widen 

 and partially fill the valleys, to carve the hills into their present 

 graceful forms, the landscape had bolder outlines, the hills were 

 higher and more rugged, the valleys were deep chasms walled by 

 steep and rocky sides. The region is now drained by the upper 

 Allegheny, the Conewango, and their tributaries. The outer edge 

 of the Chautauqua basin is identical with the highest line of the 

 highlands where these streams and their branches have their sources. 

 The waters as they flow southward converge into one outlet — the 

 Allegheny. That river, six miles below Irvington, at Thompson's 

 gap, passes through a narrow chasm, or notch cut deeply through 

 the southwestern rim of the basin. According to Prof. Carll, if a 

 dam two hundred feet in height should be built across the Allegheny 

 river at this narrow defile, it would cause the waters of these 

 streams to flow back towards their sources, flooding all this valley 

 region. The waters would rise thirty-one feet above the surface of 

 Chautauqua, and twenty-five feet higher than the Cassadaga lake, 

 and would be forced to flow through a notch sunk in the northern 

 rim of the Chautauqua basin, at Cassadaga lake, into the channel in 

 which now flows the Canadaway, to be discharged northward into 

 Lake Erie. Measurements made in the course of railroad surveys, 

 borings for oil, careful comparison of the altitude of the hills, and 

 depth of the northern drift, afford very satisfactory evidence that 

 before the glaciers invaded this basin, its waters were thus for ages 

 discharged northward. As we follow up the Conewango from 

 Warren, Pennsylvania, to the head of Cassadaga Lake, the rocky 

 floor beneath the drift and alluvium of the valley will be found to 

 lie deeper and deeper as we proceed northward. At Warren this 

 ancient river bed is eleven hundred feet above the level of the sea, 

 and is covered by one hundred feet of this drift. At Fentonville, 

 thirteen miles north of Warren, it is diminished to nine hundred 

 and sixty-four feet and is covered with twenty-seven feet of drift. 

 At Falconer, near Jamestown, it is believed to be but nine hundred 

 and nineteen feet above the sea, and is covered by fifty feet of drift. 

 At Laona, in the valley of the Canadaway, still further north, it is 

 only eight hundred feet above the tide, and at Dunkirk, on Lake 

 Erie, still less. The coast survey of Lake Erie reveals the fact that, 

 northward in a line with the channel of the Canadaway, soundings 

 extending across the lake in a direction corresponding with the 

 course of that stream are deeper than other adjacent parts of the 

 lake, indicating that the Canadaway formerly continued its course 

 northward to the ancient river bed that, it is believed, once traversed 

 Lake Erie not far from the Canadian shore. 



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