102 Scientific Intelligence. 



No. 75. — Report of Progress of Stream Measurements, 1901 ; 

 by F. H. Newell. 231 pp., 13 pis., 71 fiocs. 



No. 76. — Observations on the Flow of Rivers in the Vicinit}^ of 

 New York City ; by H. A. Pressey. 104 pp., 13 pis., 8 figs. 



2. New York State Museum. Bulletin No. 56 (Geology 5). — 

 Description of the State Geologic Map of 1901 ; by F. J. H. 

 Merrill. 34 pp. An account of geologic mapping in New 

 York State from 1820 to 1900 and the authorities for the map of 

 1901 are given. In the map itself a distinct advance is made 

 over the Preliminary Geological Map of New York published 

 in 1894, by the addition of topographical facts furnished by the 

 folio sheets of the United States Geological Survey, and by the 

 discrimination of boundaries, developed since that date. A list of 

 thirty-three contributing geologists is given whose detailed work 

 in the several counties of the State has been incorporated in the 

 revised map. 



The chief areas in which changes appear are the Pleistocene 

 geology of Long Island, the igneous and pre-Oambrian geology 

 east of the Hudson and about the Adirondacks, the Lower Paleo- 

 zoics of the latter region and the Devonian of the central and 

 southern portion of the State, The map is drawn on the same 

 scale as the 1894 map, viz : 2^ miles to the inch. 



Some confusion still exists in the mapping of the Devonian 

 formations. The Catskill-Chemung boundary of the eastern part 

 of the State is evidently drawn on the theory that its lower base 

 is at a relatively higher stratigra^^hic position on passing west- 

 ward, while the corresponding upper limits of the underlying- 

 rocks are at relatively higher horizons passing in the same direc- 

 tion. This is not a case of unconformity, but of change in the 

 character of the sediments similar to the changes occurring in the 

 Niagara, which is more calcareous to the westward, and the 

 Lower Helderberg limestone, which as a limestone is confined 

 mainly to the eastern half of the State. In other cases (viz : the 

 Genesee shale, the Tally limestone, the Onondaga limestone, etc.) 

 a similar fact is expressed by narrowing out the line of outcrop 

 to nothing or nearly nothing. These are strictly expressive of 

 distribution of formations, the definition of formation being 

 based on uniformity of lithologic characters. In the case of the 

 Portage, Ithaca and Oneonta formations, an attempt is made to 

 express differences in the fossil contents of formations occupying 

 the same stratigraphic interval. The confusion in this case arises 

 from the attempt to express two kinds of facts (distribution of 

 faunas and distribution of formations) with a single set of sj^m- 

 bols. Thus when the Portage and Ithaca formations are repre- 

 sented by an abrupt change in the color scheme, between Cayuga 

 and Seneca Lakes, the fact that the boundaries of the formations 

 are continuous shows that the change is not in the formations but 

 in the fossils. 



Although the writer is well aware of the important facts here 

 indicated, he continues to believe that no advantage will be 



