1897.] new york academy of sciences. 325 



Section of Geology. 



May nth, 1897. 



Meeting was called to order at eight o'clock, with thirty mem- 

 bers present, President Stevenson in the chair. Minutes of the 

 previous meeting were read and approved. Nominations of 

 Messrs. E. N. Dickerson and Luther Kountze were made and 

 referred to the Council under the rules. There being no other 

 business, the Section of Geology was organized and proceeded to 

 the business of the evening. 



First paper was read by Mr. D. H. Newland, on the " Occur- 

 rence and Origin of the Serpentines near New York." Mr. 

 Newland discussed the mineralogical characteristics and the 

 geographical position of the Serpentines of Staten Island ; 

 Castle Point, Hoboken ; New Rochelle and Port Chester, and 

 suggested that as regards origin they could be divided into two 

 classes; first those of Staten Island, which contain olivine, 

 diopside and tremolite and which have been probably derived 

 from some igneous rock, that had been metamorphosed before the 

 alteration to serpentine began. Second, one including the other 

 localities mentioned, whose serpentine has been apparently pro- 

 duced in the alteration of some form of sedimentary rock. 

 The paper was discussed by Dr. Ries, Dr. Martin and Professor 

 Kemp. It will appear in full in the Annals. 



The second paper of the evening was by Professor Kemp, en- 

 titled " Notes on Butte, Montana, and its Ore Deposits." Pro- 

 fessor Kemp described the development of the copper mining at 

 Butte, which has now assumed first rank in the United States. 

 He traced the geological position of the mining districts, both 

 those containing copper with silver and those containing silver 

 alone. The rocks of the region consist of two kinds of granite, 

 the older a dark basic granite which weathers easily, and the 

 second a light acidic granite. These rocks are pierced by later 

 intrusions of rhyolites, which also cut the silver veins. The 

 paper was illustrated by a large number of specimens and by a 

 series of pictures of Butte, and the surrounding region. 



