26 NEW YORK STATE MUSEUM 



the summit knoll which was the site of the triangulation station 

 (1372 feet). A farm house stands on the terrace by the highway 

 which traverses the wave-cut hillside. The highest beach line of 

 the series, shown in plate 25, is at about 1200 feet, and the lowest is 

 at about 700 feet. 



Similar conspicuous beach lines occur on the north side of the 

 large valley, and also on both sides of the lateral valley leading 

 southeast toward Newville. It would seem that the northwest winds 

 were able here to produce wave and current work that was effective 

 in carving- the soft shales. Other examples of wave action occur 

 east of Little Falls but require for clearness a higher viewpoint than 

 the railroads. 



Conspicuous shore lines lie on Sperry and Park hills eagt of 

 Boonville, in the neighborhood of 1200 feet. 



With recognition of their nature these beach lines will be found 

 in many localities throughout the areas of the Herkimer and the 

 lower lakes. 



THIRD stage: SCHOHARIE LAKE 



The only large valley opening into the Mohawk from the south is 

 the Schoharie. The river rises in the heart of the high Catskills, the 

 three headwater cols having, by the map, 1920 feet altitude. A 

 glance at the map, plate i, will show how the attitude of the valley, 

 declining northward toward the receding ice barrier, fulfilled the 

 primary condition for a glacial lake. The valley must have held 

 glacial waters at different levels. Some of the passes at the head 

 of the valley might have been blocked by local or alpine glaciers 

 during the earliest phase, but one or more of them must have been 

 the outlet for the primitive lake. Later the narrow gorge across the 

 west divide at 1560 feet must have become effective. From the 

 map it would appear that the next successive outlet would be the 

 1200 feet pass on the east divide, four miles southeast of Middle- 

 burg, at the head of the Catskill creek. However, that does not seem 

 to have been the order of events. The Middleburg pass never 

 carried a large stream, and the small flow which did occur was 

 probably northward into the Schoharie waters. This somewhat 

 surprising- fact is explained by two factors in the problem, first the 

 postglacial deformation, and second, the larger topographic relation 

 of the valley to the Hudson and Mohawk valleys. The Middleburg 

 col is 25 miles south of the parallel of the Cedarville channel. If 

 the northward uptilting of the land involved the Schoharie valley, 

 the two feet per mile of tilt would make the Cedarville pass 30 feet 



