104 Topographical Sketch of the State of New-York. 



Allegany rivers, are given in tables Nos. 5, 6, 7, 8 and 9. The 

 lowest of these is shown in table No. 7, where the Seneca lake 

 approaches to within 18 miles of the Chemung river, and is sepa- 

 rated from it by an intervening elevation of 443 1 feet above the 

 lake, or 890 feet above the ocean. The pass through which the 

 Ohio canal is constructing is 395 feet above the level of the ocean. 

 But the lowest pass to the south from any of the western lakes is 

 that between the Chicago, a small stream emptying into the south- 

 ern end of Lake Michigan, and the river Des Plaines, a branch of 

 the Illinois. The summit is here only 17 feet above Lake Michi- 

 gan, or about 617 feet above the ocean* This is the most sur- 

 prising and important hydrographical feature of our country ; as it 

 here, comparatively speaking, requires but a slight effort of art to 

 give a new outlet to the upper lakes, and to divert a portion of the 

 waters of Superior and Michigan from their present channel of the 

 St. Lawrence to that of the Missisippi. Indeed, two of the plans 

 reported by the canal commissioners of the state of Illinois^ are to 

 cut entirely through the barrier, and to supply the summit of a 

 canal through this pass with water directly from Lake Michigan. 



From the elevations of the several notches in the height of land 

 that surround Lake Ontario, we may infer the curious fact, that 

 if a sufficient barrier were to exist across the St. Lawrence river 

 above Quebec, and another at the Little Falls on the Mohawk, 

 Lake Ontario would rise to the level of Lake Superior ; the falls of 

 Niagara would disappear, and these two lakes would be merged in 

 one immense inland sea. That this has actually been the state of 

 things at some remote period in the history of our globe, is a 

 favorite opinion of many ; and indeed the appearance of the two 

 outlets, particularly that at the Little Falls, and the nature of the 

 surface of the different slopes of the lower basin, are not unfavor- 

 able to the support of this hypothesis.! 



f Appendix to Cuvier's Theory of the Earth, American edit, page 332. 



