Deckmbke 5, 1902.] 



SCIENCE. 



905 



Naturalists of the Central States will meet on 

 December 30 and 31. Chairman, S. A. Forbes; 

 secretary, C. B. Davenport, University of Chicago, 

 Chicago, 111. 



Society of American Bacteriologists will meet 

 on December 30 and 31. President, H. W. Conn; 

 vice-president, James Carroll; secretary, E. 0. 

 Jordan, University of Chicago, Chicago, 111. ; 

 council, W. H. Welch, Theobald Smith, H. L. 

 Russell, Chester, Pa. 



Society for Plant Morphology and Physiology 

 will meet during Convocation Week. President, 

 V. M. Spalding; vice-president, B. D. Halsted; 

 secretary and treasurer, W. F. Ganong, Smith 

 College, Northampton, Mass. 



Society for the Promotion of Agricultural Sci- 

 ence will meet during Convocation Week. Presi- 

 dent, W. H. Jordan; secretary, F. M. Webster, 

 Urbana, 111. 



Zoologists of the Central and Western States 

 will meet during Convocation Week. President, 

 C. B. Davenport, University of Chicago. 



SECTION OF GEOLOGY AND MINERALOGY. NEW 

 YORK ACADEMY OF SCIENCES. 



At the meeting of the Section at the Ameri- 

 can Museum of Natural History on October 

 20, the following program was presented: 



Wallace Goold Levison exhibited to the Sec- 

 tion four specimens of gneiss obtained from 

 the bed-rock in certain deep excavations at the 

 southern end of Manhattan Island. One of 

 these was collected July 20, 1902, from a 

 depth of fifty feet below the surface at the 

 corner of Broad and Exchange Streets; the 

 second was collected in the excavations at 

 40 Exchange Place, forty-five feet below the 

 surface, on July 25; two others were collected 

 at 43^9 Exchange Place, forty-five feet below 

 the surface, on July 25. Mr. Levison also 

 showed specimens of serpentine from boulders 

 found on June 19 in the excavations for the 

 Stock Exchange building on Broad Street, be- 

 tween forty and sixty feet below the surface. 



In the absence of the author, the paper by 

 Professor William H. Hobbs was read in some- 

 what condensed form by the Secretary of the 

 Section. The paper was accompanied by a 

 wealth of detailed observations too extensive 

 for reproduction, but a summary of his con- 

 elusions is as follows : 



In his introduction the author called atten- 



tion to the unusual opportunities now offered 

 for studying the geology of Manhattan Island 

 through the numerotis great engineering proj- 

 ects now being carried forward. The water- 

 ways surrounding Manhattan Island are deep 

 canons, with a depth of nearly 200 feet in 

 the East Kiver and 300 feet or more in the 

 North River, now partly filled with drift de- 

 posits and depending on the velocity of the 

 tidal currents. 



In 1865 Stevens advanced the theory that 

 the river channels were along lines of faults 

 ('longitudinal and transverse fractures')- 

 Newberry regarded the East River as the 

 lowest reach of the Housatonic River before 

 it discharged its waters into the Hudson, 

 which was then the outlet of the Laurentian 

 series of lakes, and he considered the Harlem 

 River with Spuyten Duyvil Creek a smaller 

 tributary of the Hudson. 



Dana believed that the relatively easy solu- 

 tion of certain beds of limestone determined 

 the position of the river channels. This view 

 of Dana's has been supported by Kemp and 

 Merrill, while Gratacap rejects the theory ad- 

 vanced by Stevens. 



Professor Hobbs finds that no correspondence 

 can be established between the directions of 

 the belts of limestone or dolomite and of the 

 New York water front, except within the 

 stretch from Kingsbridge to Macombs Dam 

 Bridge. Along this line too the observed 

 facts point to the occurrence of a narrow strip 

 of limestone dropped down between nearly 

 vertical faults. The sections of the Harlem 

 River which are furnished by the bridges 

 across it show clearly that it is not a simple 

 erosion valley resulting from cutting by the 

 stream. The bed of the stream is marked by 

 sudden change of level, and the Harlem seems 

 to have chosen its course quite independently 

 of the position of ridges of the harder gneiss. 

 Under the East River limestone has been 

 found at but two localities — under the chan- 

 nel east of BlackweUs Island and in one of 

 the drill holes underneath the Manhattan pier 

 of East River Bridge No. 3. The limestone 

 east of BlackweUs Island is enclosed between 

 parallel fault walls, and appears to have been 

 dropped down along them. The numerous 



