(leohxjy of Riclivioiid ('oiiiihj, S. Y. 16o 



Issaehar Cozzeiis, Jr. : "A Geological History of ManLattan 

 or New York Island," N. Y., 1843. Tins book gives a section 

 across Staten Island, and a descri])tion of tlie different forma- 

 tions found tliereon. 



Prof. Geo. H. Cook, in the " Geology of jS'ew Jersey,'* 1868, 

 and in " Report on Clays," 1878, refers to the serpentine, trap- 

 rock, sandstone and clays of 8taten Island, and to the terminal 

 glacial moraine crossing it. 



Geoloyy. — We have within the limits of onr territory, strata 

 of Archgean. of Triassic, of Cretaceous, of Quaternary, and of 

 Modern Eras ; these will be considered in the order of their ages, 

 beginning with the oldest. 



AKCii.iiAX >Stkata. 



Gratiitic Rucks. — ''J''rne granite occurs on the shore of the 

 Uppei" New York Bay, about four hundred feet southwest of the 

 Tompkinsville steamboat landing, and directly in front of the 

 old building known as Nautilus Hall. The surface of rock ex- 

 posed at low tide is about eighty feet Avide by lifty feet long ; at 

 high-water mark the rock disappears beneath a hill of drift some 

 fifteen feet in thickness. A little more of the same rock is exposed 

 at a point about two hundred feet south of the main outcrop : 

 but evei'ywhei'e else on Staten Island the granite is covered by 

 newer formations. There is reason to believe, however, that it 

 underlies the magnesian rocks, and extends in a belt of unde- 

 termined width all around the eastern edge of them, covered 

 by the glacial drift and Cretaceous strata to an unknown depth; 

 and that the same belt continues in a southwestwardly direction 

 to Arthur Kill, and thence across the State of New Jersey to 

 Trenton, where it again comes to the surface. The approximate 

 position of this belt of metamorphic rocks is shown on the ac- 

 companying map (Plate XV). 



At the exposure at Tompkinsville this granite is very coarsely 

 crystalline in structure, and for that reason could never be satis- 

 factorily employed for building purposes, even were it accessible 

 in quantity. The feldspar is orthoclase, occurs in large masses, 

 and is greatly in excess of the other two constituents ; the quartz 

 varies in color from dark brown to nearly white ; what mica 



