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NEW YORK STATE MUSEUM 



GEOGRAPHY. TOPOGRAPHY 



The relation of the geographic elements in horizontal plane is 

 shown in the maps [pi. 1-6]. The vertical relation or relief is indi- 

 cated on the maps by the contour lines which give altitude in feet 

 above ocean level, and are drawn with a vertical spacing of 20 feet. 



As a broad statement it may be said that the slope of the land sur- 

 face is toward Lake Erie. This is strictly true for the western part of 

 the area, but the eastern part inclines more to the northward, or 

 toward the Ontario basin. The slope is not a steady or uniform 

 inclination, as a large part of the fall is concentrated in a rela- 

 tively narrow belt, which is shown by the contoured maps. It is 

 along this steepest slope that the greater number of drainage chan- 

 nels occur. 



The Cattaraugus valley is the only broad embayment which 

 breaks the continuity of the Erie slopes. South of the Cattarau- 

 gus the slope is not cut by any large preglacial valleys, but the 

 surface north of Cattaraugus is more dissected. 



From State Line to the Cattaraugus valley the divide or water- 

 parting between Lake Erie and the Allegany river drainage lies only 

 some 5 to 10 miles from the lake. The altitude of the divide is 

 over 1300 feet, while the lake surface is 572 feet. It is therefore 

 apparent that the land slope in this section is very steep, falling in 

 5 to 10 miles about 700 feet from the lowest passes or cols to the 

 lake, and from the hilltops falling about 900 or 1000 feet. This 

 fact of the steep slope facing lakeward is of special importance to 

 the clear comprehension of the glacial lake history. For more 

 particular description it will be necessary to discuss the area by sec- 

 tions. 



From State Line to beyond Fredonia about one half the total fall 

 from the divide to the lake, or 400 to 500 feet, is found in about 

 1 mile of horizontal distance. This steeper slope forms the con- 

 spicuous high ground which bounds the view when looking landward 

 from the highways or the railroads. Just below the steepest slopes 

 lie the shore lines of the ancient glacial lakes. From these old 

 beaches to the present lake the land has a gentle slope, being the 

 silted and leveled floor of those extinct lakes. 



The Cattaraugus valley carries the divide far inland (eastward), 

 the farthest points being some 40 miles from Lake Erie. The old 

 beaches and glacial stream channels, however, curve up the valley 

 only as far as Gowanda. 



From the Cattaraugus embayment to Hamburg the topographic 

 features are quite similar to those west of the valley. Beyond 



