16 PHILOSOPHICAL SOCIETY OF WASHINGTON. 
the Anthropological Society and listen to an address by its president, 
Major J. W. PowEL. " 
The Chair announced the election to membership of Messrs. Car- 
Los ALBERT KernastTon, RoLAnD Durr Irvine and ARTEMAS 
MARTIN. 
Mr. T. C. CHAMBERLIN completed his communication 
ON THE VARYING ATTITUDES OF FORMER LEVEL SURFACES IN 
THE GREAT LAKE REGION AND THE APPLICABILITY OF 
PROPOSED EXPLANATIONS. 
Remarks were made by Mr. Dutron. 
Mr. R. D. Irvine made a communication on 
THE ENLARGEMENT OF MINERAL FRAGMENTS AS A FACTOR IN 
ROCK ALTERATION, 
which was discussed by Messrs. Ippines, DitteR, Durron, and 
LAWRENCE. 
284TH MEETING. Marca 27, 1886. 
The President in the Chair. 
Thirty-three members and guests present. 
Mr. I. C. RusseLt made a communication on 
THE SUBAERIAL DECAY OF ROCKS AND THE ORIGIN OF THE RED 
CLAY OF CERTAIN FORMATIONS. 
This was discussed by Prof. Joun 8. Newserry, of New York 
city, and by Messrs. Goopr, Darton, IrvinG, and CHAMBERLIN. 
Mr. Romyn Hircucock made a communication on 
RECENT IMPROVEMENTS IN MICROSCOPIC OBJECTIVES, WITH DEMON- 
STRATION OF THE RESOLVING POWER OF A NEW 1#16TH INCH. 
Remarks were made by the President. 
