GEOLOGICAL LIGHT FROM THE CATSKILL AQUEDUCT 711 



rocks are a peculiar and distinct type, which, so far as known, have not pre- 

 viously been described in geology. Gold Hill, Contractors Hill, and Empire 

 bridge breccia and some of the Paraiso breccias are of this type. 



geological light from the catskill aqueduct 



by charles p. berkey 



Discussion 



Dr. J. W. Spencer : The topographic features of the Hudson Valley suggests 

 that the Highlands, near West Point, formed a dividing ridge, from which the 

 drainage passed both southward to New York Harbor and northward to 

 Champlain and the Saint Lawrence, although it is now trenched by the river 

 channel. The country has risen in post-Glacial times to the north, as shown 

 by Woodworth, but so far this deformation and the filling of the buried chan- 

 nels is not sufficient to account for the depth of the pre-Glacial valley at Storm 

 King, but deeper channels may be found. In the meanwhile there is a dispo- 

 sition to conclude that it was due to glacial erosion; but, if so, how did it 

 occur in the very hard rocks when the lake basins in soft rocks were not due 

 to glacial erosion? This question needs to be answered. Recent gravity meas- 

 urements suggest a faulting in this region, and much must be learned before 

 the origin of the deep channel at Storm King can be explained. 



A CLASSIFICATION OF MARINE DEPOSITS 

 BY AMADEUS W. GRABAU 



(Abstract) 



Of the published classifications of marine deposits that of Murray and Re- 

 nard (Challenger report) is perhaps the best known, being generally found in 

 text-books. Its three main divisions into deep sea, shallow water, and littoral, 

 or shore, are based on the locality of deposition, the source and character of 

 the material receiving only minor consideration. While convenient, such a 

 classification can not be considered strictly scientific. Otto Krummel (Hand- 

 buch der Ozeanographie, Band I, p. 152) gives a more satisfactory subdivision, 

 though his divisions are not always of the same type. 1 He uses the term lit- 

 toral in the wide sense, including the region from high water to the edge of 

 the continental shelf, a use of the term which to me seems the most logical and 

 satisfactory, as elsewhere advocated. 



In any logical classification of marine deposits the distinction between areas 

 of deposition and types of deposits must be clearly kept in mind. The areas of 

 deposition comprise (1) the littoral district, with its two zones, (a) the shore 

 and (b) the neritic; (2) the bathyl district, and (3) the abyssal district. 

 Oceanic deposits must be classified first as to their origin and next as to their 

 mode of occurrence. This is aimed at in the following table of oceanic de- 

 posits : 2 



1 For a statement of Murray's and KrUmmel's classification, with criticism, see A. W. 

 Grabau : "Principles of Stratigraphy," i>]>. 643-645. 



2 For details see A. W. Grabau: "Principles of Stratigraphy," chapters ix (chemical), 

 x and xi (organic), and xv (clastic) deposits. 



