﻿22 NEW YORK STATE MUSEUM 



easterly direction, with sharply cut ravines heading against it on 

 both sides, marking the extreme heads of the small streams which 

 flowed on the one hand northeast to the St Lawrence, and on the 

 other hand southwest to the Ontario drainage. On the Clayton 

 quadrangle the French creek valley belongs to the former, and 

 the Chaumont river valley to the latter category; on the Alexandria 

 most of the country was on the St Lawrence side of the divide, 

 the valleys of Crooked creek, Cranberry creek, Butterfield lake- 

 Black creek, and the valleys now occupied by the other lakes be- 

 longing there, while Mullet creek valley drained the other way ; on 

 the Theresa the valley into which the Indian river breaks at Theresa 

 village seems to belong to the easterly drainage, while the remain- 

 der of the valleys on the quadrangle carried water to the westward 

 drainage. 



The valleys excepted, the prominent topographic fe.ature of the 

 region is the rock cliffs, usually low, which mark the edges of out- 

 crop of the various formations, and which owe most of their pres- 

 ent relief to the wear which followed the considerable uplift. In 

 general, each rock formation of the region is somewhat less resistant 

 to wear than the formation beneath and somewhat more so than 

 the formation above. Hence the overlying formation tends to be 

 slowly stripped away from that beneath, which yields more slowly 

 and, because of the nearly horizontal attitude of the rocks, remains 

 as a comparatively flat terrace, above whose level stands the re- 

 ceding front of the overlying formation,- while in the opposite di- 

 rection the lower formation has its terrace terminated by a similar 

 front which drops down to the level of the formation next under- 

 lying. Each formation then shows a receding front of the sort, 

 the Theresa above the Potsdam, the Pamelia above the Theresa and 

 so on. Because of the greater thickness of the formations the 

 Trenton and Pamelia fronts are the highest and the most conspicu- 

 ous as topographic features. The Trenton front only gets within 

 the map limits in the extreme southeast corner of the Theresa 

 sheet, but the Pamelia front can be followed as a cliff of more or 

 less prominence across the Theresa and Clayton quadrangles, until 

 the formation is lost beneath the river. This is the kind of topog- 

 raphy invariably produced when a district of nearly horizontal 

 rock formations of varying resistance is being worn down, but the 

 general type is magnificently illustrated in the region here. 



