ANCIENT WATER LEVELS OF CH A MPLAIN— HUDSON VALLEYS 117 



The kame or ice contact slope of the terrace is strewn with 

 angular stones up to 6 inches in diameter. A block of limestone 

 lies in the morainal belt near the railroad, also ice-scratched 

 pebbles and boulders up to 2 feet in diameter occur near the Bay 

 View terrace. 



The structure of the terrace shows that it is composed in part 

 of clays and in part of sands and gravels. South of Washington's 

 Headquarters Museum the clays appear to rise not higher than 30 

 feet above the river. Other points reveal a yellowish oxidized clay 

 top in the plain with gravels in foreset beds beneath. 



On the south side of Quassaic creek well defined foreset beds of 

 gravel and sand form the principal part of the section down to 



E 



HUDSON RIVER. 



Fig. 12 Terrace at Newburg X. Y. Q, valley of Quassaic creek 



the level of the West Shore Railroad tracks. These foreset beds 

 dip eastward into the river gorge, showing that the terrace was 

 built outward in that direction by the flow of water from the ice 

 front lying back of the terrace [see fig. 12]. 



Another partial section on the north side of Quassaic creek, 

 showed the following details. 



LOCAL SECTION IN NEWBURG TERRACE 



Feet 



Gravel, at surface 1 



Sand 1 



Clay, stratified 8 



Sand, clayey 1.5 



Gravel, fine shaly river pebbles 2 



Clay above river about 60 



These clays near the railroad track dip gently east and appear 

 to be locally eroded. This erosion is further evidenced by the 

 manner in which they are replaced by gravels and sands w^ith fore- 

 set beds south of Quassaic creek. The interstratification of sands 

 and clays in the above partial section is instructive as showing 

 that clay making went on evidently at this stage in close 



