GEOLOGY AND GEOGRAPHY OF CLAY DEPOSITS 121 



Long Island Clays 



Long Island is made up of a series of sands, gravels and 

 clays, which form two parallel ranges of hills in the northern 

 half of the island, while the southern half is a flat plain. The 

 most southern of the ranges represents the limit of the drift.* 



The clay beds are exposed along the north shore of the island 

 and at several points along the main line of the Long Island 

 railroad. In describing them I have gone east along the north 

 shore and come back through the center of the island. 



In a paper on the geology of Long Island, (previously cited) 

 Dr. F. J. H. Merrill describes in detail the formations exposed on 

 the island, and mentions the insufficiency of data necessary to 

 afford definite conclusions concerning the sequence of geological 

 events. Examinations of the various clay outcrops on the 

 island made since show that eight years has made considerable 

 changes; permitting the collection of additional data and 

 obliterating many localities described by him. With the excep- 

 tion of four similar deposits on the north shore, all the clay beds 

 as exposed at the brick yards are rather unique in appearance. 



The most western clay outcrop on Long Island, of which the 

 writer has any knowledge, is on Elm Point near Great Neck.ij: 

 There is here a bed of stoneware clay over 30 feet thick and 

 overlain by 15 to 20 feet of yellow gravel and drift. The clay is 

 dark gray and contains streaks of lignite in a good state of 

 preservation. In appearance the clay resembles the Cretaceous 

 ones of New Jersey and will doubtless prove to be of the same 

 age. The overlying yellow gravel contains sandstone concretions 

 a/ud also sandstone fragments containing Cretaceous leaves.** 



There is an outcrop of clay at Glen Cove on the east shore of 

 Hempstead Harbor and at the mouth of Mosquito Inlet. This 

 has long been considered of Cretaceous age from the plant 

 remains foundf in sandstone fragments embedded in the clay. The 

 layers of the latter are blue, red, black and yellow, and dip northeast 

 10°-15°. Near this locality and on the south shore of Mosquito 

 Inlet is an outcrop of pink clay, belonging to Carpenter f>ros. 

 and used for firebrick and stoneware. Dipping under it to the 



* For a detailed account of the topography of Long Island see Mather, Geology of New York 

 (Ist Dist.) 1843 ; W. Upham, A. J. 8. Ill, 18.; F. J. H. Merrill, Geology of U>ng Island, Ann. 

 N Y Acad. 8ci, 1834. 



t H. Ri>8. Notes on the clays of New York State.— Trans. N. Y. Acad. 8cl., XII. 



** C L Pollard, Note on Cretaceous leaves from Elm Pt., L. I.— Trans. N. Y. Acad. Sci., XIII. 



+ A. Hollick, Trans. N. Y. Acad. 8ci., XIL 



