"^ [July If, 



Aii offer from the State Librarian of Michigan to ex- 

 change was accepted. 



Donations for the Library were received from the Acade- 

 mies at St. Petersburg, Berlin, Brussels, Rome and Minne- 

 apolis; from the Geographical Societies of Russia, Paris and 

 Bordeaux; the Observatories at Prag and Adelaide; from 

 the Bureau des Longitudes; London Astronomical Society; 

 and the Corporation of the City of London ; Essex Institute' ; 

 Boston Society of Natural History; Brooklyn Entomologi- 

 cal Society; American Chemical Society and the New York 

 Mercantile Library Association; Franklin Institute, Ameri- 

 can Pharmaceutical Association, Union League and Engi- 

 neers' Club of Philadelphia; Smithsonian Institution; and 

 Argentine Scientific Society; Yale College; Wabash Col- 

 lege; U. S. Engineers' Department; Mexican Agricultural 

 Bureau; Melbourne Mining Bureau; Young Men's Associa- 

 tion at Buffalo; Dr. Scheffler, of Braunschweig; Canadian 

 Naturalist; Silliman's Journal; New York Entomological 

 Society, and Mercantile Library; Journal of Pharmacy, 

 Journal of the Medical Sciences, Pennyslvania Magazine of 

 History, &c, Prof. Frazer, Dr. Genth, Mr. Benson, Prof. 

 Jacques, and Dr. Gross. 



A communication was received, entitled, "On Pyrophyl- 

 lite" from Schuylkill Co., Pa., by Dr. F. A. Genth (p. 279). 



Mr. Lesley described a recently discovered ancient buried 

 river channel crossing the Allegheny river twice, from the 

 mouth of the Clarion, above and below Parker, at the north- 

 ern limit of Armstrong County. 



As Mr. Carl] has shown that the preglacial Allegheny river had its 

 luads in the high ridge south of Tidioute, in Venango County, it is evident 

 that the Clarion river was then the main Allegheny river ; which explains 

 the ancient douhle curve at Parker. After the ice had retreated from the 

 northern country, leaving all the valleys choked with drift, the combined 

 waters which until then had entered the basin of Lake Erie, at Dunkirk, 

 in New York State, broke away through the ridge below Tidioute, and 

 cut the present straight channel at Parker, across and 100 feet lower than 

 the ancient channel. 



Pending nominations No. 878 to 884, and new nomination 

 885, were read. 



