114 NEW YORK STATE MUSEUM 



Oa J. O'Brien's property: 



Clay 20 feet 



Quicksand 25 " 



Hardpan ... 2 " 



Gravel 



Total thickness 47 " 



The clay deposits of Hudson, Stockport and Stuyvesant are 

 like those at Coeymans Landing, being overlaid in most places 

 by a few feet of loam and underlain by dark sand and gravel. 

 At Stockport two ice-scratched bowlders were found in the clay ; 

 one of them three feet in diameter, the other three times as 

 large. To the north of Brousseau's yard at Stuyvesant the 

 surface material is stratified sand, 15 feet of it being exposed 

 thus far. 



The delta deposits of the streams tributary to the Hudson River 

 are extremely interesting. They give us an idea of the size of 

 the rivers flowing into the Hudson Yalley when it formed an 

 €stuary, and also indicate the amount of depression which took 

 place at those localities. Ml three portions of a delta may be 

 observed in the ancient deltas on the Hudson; they are tlie thin 

 layers of loamy clay which form the secondary alluvial cone of 

 the delta, the cross-stratified sand and gravel and the overlying 

 unassorted material. This latter was observed at Haverstraw, 

 IN"ew Windsor, Low Point and Dutchess Junction. 



The following streams between 'New York and Poughkeepsie 

 have formed delta deposits ; (as noted by Dr. Merrill.*) Wap- 

 pinger Creek, New Hamburg ; Fishkill Creek ; Indian Creek, Cold 

 Spring; Peekskill; Croton River; Pocahtico River, Tarry town ; 

 Sawmill River, Yonkers ; Tibbitt's Brook, Yan Cortland ; Minis- 

 ceongo Creek, Haverstraw ; Cedar Pond Brook, Haverstraw ; 

 Moodna River, Cornwall ; and Quassaic Creek, Newburg. At the 

 present day but traces of these deposits remain, and the streams 

 which formed them have cut down through them below tide- 

 level. Dr. Merrill thinks it highly probable that these deltas 

 once filled a large portion of the valley in the Highlands. At 

 Roseton, as already mentioned, there is a deposit which may have 

 come from the delta of Wappinger Creek. Also at Jones' Point 

 opposite Peekskill there is a terrace composed of transported 



♦Amer. Jour. Scl. iii, XLI, June 1891. 



