lOS 



NKW YORK STATE MUSEUM 



at or iioar its pivsoiit noriln'rii end. These gravels coming to 

 repose on the terminal slope under water formed successive 

 inclined stratified additions to the deposit in this direction. The 

 base of the deposit toward the southern end is sand and fine silt 

 or rock-flour almost clayey in consistency. This finer material 

 represents that which was washed off to the bottom at the foot 

 of the gix)wing embankment this being pushed out into the opc^n 

 water in that direction. These materials formed horizontal beds 

 in front of the growing deltalike bar and were successively en- 

 croached on by the foot of each layer of inclined gravel and sand 

 deposited on the growing slope of the bar. In this way origi- 



S N 



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•^ .-. •• -', 







Fiff 10. Section at southern end of Jones Point terrace in July li)0(X showing- at base 

 horizontal bedsof (1) sand, and rock-Hour, overlain by southward inclined beds (dip 30°), of 

 (i) coarse g-ravel with cobbles uj) to 6 inches, and {'i) tine gravel up to 3 inches. 



nated the unconformity at the base of the inclined beds. There 

 was no erosion of the horizontal beds for they were in the 

 deeper water willi strong ( un-eiits moving only near the surface. 

 The occurrence of coarse cobbles ranging up to 6 inches in 

 diameter in these foreset beds nearly half a mile from the 

 northern end of the embankment is evidence of strong currents 

 running to the southward and on the concave shore of the 

 ju-csent Hudson river wlicic under existing conditions or with a 

 higher water level it is difficult to conceive of a current of the 

 river working at the level of this deposit being so directed as to 

 produce the observed result. There ai)pear to be but two pos- 

 sibilities concerning the circumstances of the formation of this 

 terrace: either it was built by a strong southward flowing shore 

 current during a time when the water level in this part of the 

 valley stood about 100 feet higher than now or it was con- 

 si i-iided in n ^l;iri;il side channel at a time when the glacier filled 

 the gorge in (lie Highlands and protruded southward as glaciers 



