De Geer.] 
454 
[May xS, 
COUNCILLORS FOR THREE YEARS, 
♦Edward T. Bouve. 
* Henry Brooks. 
* William A. Jeffries. 
* Miss Susannah Minns. 
♦John Ritchie, Jr. 
* Alfred P. Rockwell. 
* Charles S. Sargent. 
* Warren Upham. 
COUNCILLORS FOR TWO YEARS, 
S. L. Abbot. 
Henry P. Bowditch. 
* William S. Bryant. 
William M. Davis. 
William G. Earlow. 
Edward G. Gardiner. 
Henry W. Haynes. 
Mrs. Ellen H. Richards. 
COUNCILLORS FOR ONE YEAR, 
George H. Barton. 
William Brewster. 
Miss Cora H. Clarke 
Robert T. Jackson. 
* Nathaniel T. Kidder. 
Edward S. Morse. 
William T. Sedgwick. 
Nathaniel S. S haler. 
Thomas T. Bouve. 
John Cummings. 
councillors ex-officiis, 
George L. Goodale 
F. W. Putnam. 
Samuel H. Scudder. 
May 18, 1892. 
President W. H. Niles in the chair. Sixty-two persons present. 
The following papers were read : — 
ON PLEISTOCENE CHANGES OF LEVEL IN 
EASTERN NORTH AMERICA. 
BY BARON GERARD DE GEER, 
of the Geological Survey of Sweden . 
(Walker Prize Essay, 1892.) 
One of the most important principles upon which geology is 
founded is the theory of continental changes of level. The main 
points of this theory seem, in several cases, to have been well es- 
tablished by American geologists. Thus it lias been pointed out, 
that to account for sandstone several thousand feet in thickness, 
and other deposits in shallow water, it is necessary to assume 
that the sea-bottom was sinking at the same rate that the sediment 
