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REVIEWS 



at Princess Bay Light. The Pensauken is thought to be no older than some of the 

 glacial deposits, though not of glacial origin. 



The growth of the ice-sheet, the recurrent glaciations, and the characteristics of 

 glacial drift are briefly discussed before taking up the features and deposits found 

 within the New York area. The topography, topographic relations, and composition 

 of the moraine on Staten and Long Island, the stratified drift south of the moraine, 

 and the ground moraine to the north, are discussed in some detail, after which strise, 

 mixed drift, and stratified drift north of the moraine are considered, and attention is 

 called to a surface loam, which, it is thought, may have originated in several different 

 wavs. Gravel near Rockaway on Long Island, though nonglacial, is thought to be 

 of late Glacial age or even younger, and is correlated with the Cape May formation. 

 The oscillation of the land, stream erosion, shore erosion, and weathering in postgla- 

 cial time are then considered. The evidence concerning land oscillation is found to 

 be indecisive. The slight amount of weathering of the drift surface, of stream erosion, 

 and shore erosion testify to the briefness of the postglacial epoch. 



Stevenson, A. E. Glacial Action in Schoharie Valley. Ann. N. Y. Acad. 

 Sci., Vol. X, igoi. 

 Not examined. 



Upham, Warren. Preglacial Erosion in the Coicrse of the Niagara 

 Gorge and its Relation to Estimates of Postglacial Time. Am. Geol., 

 Vol. XXVIII, pp. 235-44, 1901. 



The St. David's channel is thought to be preglacial rather than interglacial, 

 because of its wide mouth. Fish Creek, a small eastern tributary of the Niagara, 

 entering just south of the Niagara Escarpment, is thought to be occupying a pregla- 

 cial valley which continued in the course of the Niagara River (reversed) to connect 

 with the St. David's channel at the whirlpool. This would render but a small amount 

 of rock excavation necessary in opening a part of the gorge below the whirlpool, and 

 would materially affect estimates of the length of postglacial time. On the assump- 

 tion that much of the northward differential uplift followed very closely upon the ice 

 retreat (an assumption which Fairchild's observations at the east end of Lake Ontario 

 show to be unfounded for that region) Upham concludes that the three upper lakes 

 could not have discharged through either the Trent or the Mattawa valley, and consid- 

 ers the erosion of the Niagara gorge the work of a stream whose volume never was 

 much less than the present and for the early part of the erosion was much greater. 

 From this it is reasoned that postglacial time has been very brief, 7,000 years being 

 considered ample for that part of it involved in cutting the Niagara gorge. 



WooDWORTH, J. B. Pleistocene Geology of PortioJis of Nassau and Queens 

 Counties, New York. Bui. 48, N. Y. State Museum, pp. 53, 1901. 

 This bulletin is the first of a series which is planned for the discussion of the 

 Pleistocene geology of the eastern part of New York. It embraces a discussion of 

 topographic features, glacial deposits. Pleistocene history, and postglacial changes 

 and processes now in action, but deals mainly with the Pleistocene deposits. 



The topographic features embrace a morainic system with two ridges separated 

 by a sand plain, and south of this morainic system an extensive outwash plain sloping 

 from a morainic border to the sea. North of the morainic system is a tract of uneven 



