GEOLOGICAL DISCUSSION. 25 



Staten Island is defined both on the map and in the description, and is correlated 

 with the Cretaceous of New Jersey on the basis of the fossil plants found in it. 



About this time the problem of an additional water supply for New^ York City 

 was receiving earnest attention, with the result that numerous investigations were 

 made which involved reports upon the geology of areas from wmich such supplies 

 might be obtained. Both Staten Island and Long Island received attention in this 

 connection, and during the progress of the work several new facts were incidentally 

 brought to light in relation to the surficial and underlying strata. a 



Finally may be mentioned J. B. Woodworth's paper on the " Pleistocene Geology 

 of Portions of Nassau County and Borough of Queens/' 6 in which the glacial phe- 

 nomena of that area are described and illustrated in considerable detail. 



In addition to the preceding references to the principal papers on the geology of 

 the region a number of briefer notes and memoranda by some of the same authors 

 and others could be given, but those quoted probably include essentially all of the 

 diverse opinions which have been expressed from time to time, and indicate the 

 necessity that existed for careful and critical examination of all the available facts 

 in connection with the topographic features, stratigraphy, and paleontology of the 



region. 



GEOLOGICAL discussion. 



GENERAL CHARACTERISTICS OF THE PLANT-BEARING DEPOSITS. 



The deposits in wmich fossil plants have been found at the localities previously 

 mentioned consist, in part, of clays, sands, and gravels, lithologically similar to the 

 Cretaceous strata of the mainland, as represented in the Karitan and Cliffwood forma- 

 tions of New Jersey, and, in part, of morainal material derived from them. 



The occurrence of ferruginous shale and concretions, while not altogether absent 

 on the mainland, reaches such a development on the islands as to constitute a dis- 

 tinct and characteristic lithologic feature of the insular deposits at a number of locali- 

 ties. The shaly condition is especially well developed in connection with the clay 

 exposure on the shore a short distance west of the Glen Cove landing, Long Island, 

 while the concretionary phase is best exemplified in the Gay Head section on Marthas 

 Vineyard. 



Both kinds of this hard material are also conspicuous constituents of the moraine 

 throughout almost its entire insular extent, frequently containing plant remains and 

 affording evidence of the former presence of Cretaceous deposits at or near to locali- 

 ties where all other indications have been entirely obliterated. It was the discovery 

 of specimens of this kind that first indicated the existence of a Cretaceous flora in 

 place on Staten Island and Long Island, and finally led to its identification elsewhere. 



Whether this material is largely a result of glacial erosion and disturbance of the Cre- 

 taceous clays, which have thus become exposed to oxidizing influences and consequent 



a I. Freeman, John R., Report on New York's water supply, etc.; New York, Martin B. Brown & Co., 1900, 8 vo., pp. 587 



maps, figures, and diagrams. 

 II. Crosby, W. O., Outline of the geology of Long Island in its relations to the public water supply: Tech. Quart, vol. 



13, 1900, pp. 100-119. 



III. Fuller, M. L., Probable pre-Kansan and Iowan deposits of Long Island, N. Y.: Am. Geol., vol. 32, 1903, pp. 308-312. 



IV. Veatch, A. C, The diversity of the Glacial period on Long Island: Jour. Geol., vol. 11, 1903, pp. 762-776. 



V. Veatch, A. C, and others, Underground water resources of Long Island, New York: Prof. Paper U. S. Geol. 

 Survey No. 44, 1906. 



b Bull. New York State Mus. No. 48. 1901. 



