•2.2 NEW YORK STATE MUSEUM 



Lawrence-Ontario the former dominated in the Mohawk region, 

 for the reason that the course was more direct and the distance less. 

 But as the ice body thinned this advantage was overbalanced by 

 the narrower and more restricted cross section of the Champlain 

 valley as compared with the open, though somewhat higher St 

 Lawrence. 



At the time of the ice retreat the north boundary of the State 

 was depressed at least 600 feet below its present altitude and the 

 entire Mohawk area was lower than now and probably somewhat 

 lower relatively to central New York. 



SECOND STAGE : HERKIMER LAKE 



The sketch map, plate i, shows the southern limits of the Mohawk 

 drainage, including the Schoharie valley. The passes across the 

 divide which bear evidence of stream flow are also indicated. 



The first step in the study of the glacial lake history is to de- 

 termine the altitudes of the water planes and to find the points of 

 overflow or the correlating outlets, keeping in mind the fact of 

 some later northward uplift. It was discovered that very extensive 

 sand plains north and east of Forestport and near the hamlets of 

 Grant, Gray and Ohio, in the basins of the upper Black river and of 

 West Canada creek, had an elevation of 1440 feet, while other 

 extensive plains ranged in the neighborhood of 1300 feet. Examina- 

 tion of the passes leading out of the Mohawk basin shows a strong 

 river-cut channel in limestone at the head of the Otsego valley and 

 seven miles east of Richfield Springs, with an altitude of about 1360 

 feet. Another capacious channel of perfect form lies at Cedarville, 

 eight miles northwest of Richfield Springs, at the head of the Una- 

 dilla-Susquehanna, with an elevation of 1220 feet. Farther west is 

 only one pass with lower altitude than the Cedarville, at Bouckvplle, 

 four miles north of Hamilton, leading to the Chenango river, with 

 an elevation of 11 50 feet. Passes at Richfield Junction and at 

 Sangerfield have elevations of 1260 and 1240 feet. All these features 

 are shown on the Richfield Springs, Winfield, Sang-erfield and Mor- 

 risville sheets, and the two passes first named are shown on plate 5. 

 The passes on the east can have no relation to the Ohio water 

 planes, being either too high or too low, with the exception of one 

 four miles south of Middleburg in the Schoharie valley, at the head 

 of the Catskill creek, with elevation 1200 feet. Examination of this 

 col shows a tiny stream cutting across the summit but incapable of 

 carrying a respectable creek ; and the flow there was probably 

 northward. 



