500 NEW YOKK STATE MUSEUM 



extensive erosion which has taken place, they are usually narrow, 

 and it is only at sheltered points, like Port Kent and Beauport, 

 that they are specially prominent. The section involved is yel- 

 lowish brown sand, yellowish brown clay and stiff blue clay, the 

 latter being rather calcareous. The upper clay is somewhat 

 silicious, and its coloring is due to the weathering of the lower 

 layer. This formaticn has a thickness of about 15 feet, but 

 sometimes, as at Burlington, it reaches a thickness of 100 feet. 

 Isolated bowlders are occasionally found in the clays. The clays 

 are usually horizontally stratified, and contortions of the layers 

 are extremely rare. Numerous marine Quaternary fossils have 

 been found in the overlying sands ; the skeleton of a whale has 

 also been found in them. 



Openings have been made in these deposits for the purpose of 

 obtaining brick clays at Plattsburg and a few other localities. 



Long Island Clays. 



Cl&y beds are exposed along the north shore of the island and 

 at several points along the main line of the Long Island railroad. 



There is still some doubt as to the exact conditions under 

 which the beds of clay and gravel which form the greater por- 

 tion of Long Island were deposited, but it is probable that the 

 clays represent shallow water marine deposits of Cretaceous and 

 Tertiary age. The overlying sands and gravels have in most 

 instances a cross-bedded structure, with a south dip, and were 

 probably deposited by swift currents as stated by Dr. Merrill. 



The age of the clays is still largely a matter of speculation, 

 and will probably remain so in many cases unless palaBontologic 

 evidence is forthcoming. Those on Gardiner's Island are quite 

 recent, as shown by the contained fossils, and the clay on Little 

 Neck, near Northport, is Cretaceous. The age of the Glen Cove 

 clay is probably Cretaceous . 



Cretaceous leaves in fragments of ferruginous sandstone have 

 been found along the north shore of Long Island from Great 

 Neck to Montauk Point,* but they are usually much worn and 

 scratched and have evidently been transported from some dis- 

 tant source. The clays at Center Island, West Neck, Fresh 



* A. Hollick, Notes on Geology of North Shore of Long Island, Trans. N. Y. Acad. Sci., XIII. 



