November 30, 1906.] 



SCIENCE, 



691 



NEW YORK ACADEMY OF SCIENCES. SECTION OF 

 GEOLOGY AND MINERALOGY. 



At a meeting on Monday, October 8, the 

 following papers were read: 



Notes on the Microscopic Examination of the 

 Opaque Constituents of Ore Bodies: Dr. 

 William Campbell. (Illustrated with lan- 

 tern slides.) 



The first part of the paper dealt with the 

 preparation of the specimen for examination; 

 of the various types of microscopes used; and 

 the means of obtaining illumination by re- 

 flected light. ISText 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; Sudbury, 

 Out.; southeast Missouri, etc. 



Notes on the Preglacial Channels of the 

 Lower Hudson Valley as revealed l>y Recent 

 Borings: Dr. C. P. Berkey. 

 Borings made by the Board of Water Sup- 

 ply of New York City, in connection with the 

 project of bringing water from the Catskill 

 Mountains, have shown the existence of nu- 

 merous deeply buried channels representing 

 preglacial stream courses. Many of them in- 

 dicate channels cut far below present sea level 

 at considerable distances back from the Hud- 

 son River. From engineering records it ap- 

 pears that the depth to bed-rock in the Hud- 

 son 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 through- 

 out a large part of its lower course. 



Notes on the Character and Origin of the 



Pottsville Formation of the Appalachian 



Region: Dr. A. W. Grabau. 



The character of the overlap of the several 



divisions of the Pottsville, and the material 



and type of cross-bedding were discussed and 



the conclusion reached that the formation is 

 of the nature of an alluvial cone — or several 

 confluent ones, with occasional raarine inter- 

 calations. 



Professor D. S. Martin exhibited a large 

 crystal of pink beryl, which he had lately 

 obtained at Haddam Neck, Conn. The old 

 quarry in the albite pegmatite at this locality, 

 long famous for its colored tourmalines, is 

 not now being worked; but a new one has 

 been opened closely adjacent, and apparently 

 on a continuation of the same vein or dike. 

 This one has yielded less tourmaline than the 

 former, but much more beryl, and particularly 

 the heretofore very rare pink variety. Of 

 these, a number of fine large crystals have 

 been obtained, comparable with those lately 

 developed from the gem-tourmaline mines in 

 San Diego County, California. 



The present specimen measures about four 

 inches in both length and diameter; it is a 

 fine termination, of the type characteristic of 

 this variety. It has been recently shown by 

 Ford (Am. J. Sci., Sept., 1906) that these 

 pink beryls, from whatever locality, present a 

 peculiar type of crystallization. Instead of 

 the long hexagonal prism with flat basal term- 

 ination, usually seen in the green beryls of 

 New England, the pink ones tend to a strong 

 development of pyramidal planes, especially 

 the pyramid of the second order (s), while 

 the prismatic faces are short. It is very in- 

 teresting to see how perfectly this crystal, 

 from a new locality, conforms to this state- 

 ment. It shows three very short and partly 

 broken prismatic faces, and a large and per- 

 fect hexagonal pyramid of the second order; 

 the basal plane is reduced to a small irregular 

 face about one inch in its longest diameter, 

 and bears several shallow pits or depressions, 

 of which the inclined sides conform to the 

 pyramid of the first order. Altogether, the 

 specimen is one of unusual interest, 



%. W. G:B,kRk\5, Secretary. 



THE AMERICAN CHEMICAL SOCIETY. NEW YORK 

 SECTION. 



The first regular meeting of this section 

 was held on November 9 at the Chemists' 

 Club, 108 W. 55th Street. 



