294 ANNALS NEW YORK ACADEMY OF SCIENCES 



William Campbell, Notes on the Microscopic Examination of the 



Opaque Constituents of Ore Bodies. 



C. P. Berkey, Notes on the Preglacial Channels of the Lower 



Hudson Valley as Revealed by Recent Borings. 

 A. W. Grabau, Notes on the Character and Origix\ of the 



Pottsville Formation of the Appalachian 

 Region. 



D. S. Martin, A Beryl from Haddam Neck, Connecticut. 



Brief discussions followed several of the papers. 



Summary of Papers. 



Dr. Campbell's paper dealt with the preparation of the specimen for 

 examination; of the various types of microscopes used; and the means of 

 obtaining illumination by reflected light. Next the paragenesis of the 

 constituents of certain alloys was shown by microphotographs. Lastly 

 the methods were applied to the opaque constituents of ores from Butte; 

 the Cochise district of Arizona; Ducktown, Tenn.; Rossland, B. C; Sud- 

 bury, Out.; southeast Missouri, etc. 



Dr. Berkey said that borings made by the Board of Water Supply of 

 New York City, in connection with the project of bringing water from the 

 Catskill Mountains, had shown the existence of numerous deeply buried 

 channels representing preglacial stream courses. Many of them indicate 

 channels cut far below present sea level at considerable distances back from 

 the Hudson River. From engineering records it appears that the depth to 

 bed-rock in the Hudson River has never been determined at any point 

 in its lower course. Profiles of supposed rock-bottom based upon wash- 

 borings have been proven by the recent work to represent simply the bottom 

 of the finer silt filling. The results show that more than 200 feet of more 

 compact material lies below this silt at the point now being tested, and that 

 the rock-bottom of the ancient Hudson lies more than 450 feet below the 

 present river level throughout a large part of its lower course. 



Dr. Grabau discussed the character of the overlap of the several divi- 

 sions of the Pottsville, and the material and type of cross-bedding and 

 reached the conclusion that the formation is of the nature of an alluvial 

 cone — or several confluent ones, with occasional marine intercalations. 



Professor Martin exhibited a large crystal of pink beryl, which he had 

 lately obtained at Haddam Neck, Conn. The old quarry in the albite peg- 

 matite at this locality, long famous for its colored tourmalines, is not now 

 being worked, but a new one has been opened closely adjacent, and appar- 



