Pleistocene Papers at the Madison Meetings. 171 
ward ascent of the lake Agassiz beaches, and the marine beds 
about Hudson and James bays. 
Mr. McGee, in discussion, stated that erosion by the Mis- 
sissippi river near its mouth was 1,000 feet in vertical depth 
after the deposition of the Lafayette beds, which he thinks 
to be a marine or estuarine formation, succeeded by consider- 
able uplift of the continent. The forest beds of Iowa seem 
to him to prove a long interglacial time, with at least two dis- 
tinct epochs of glaciation; and the best evidence of such 
division of the Ice age appears to be the different depths of 
stream cutting in the earlier and later drift. 
Prof. Spencek regarded the correlation of the Lafayette and 
Saskatchewan formations as doubtful, the former being estu- 
arine. 
Prof. R. D. Salisbury also considered the Lafayette forma- 
tion as marine, and thought it far older than the glacial drift, 
as shown by its great erosion previous to the loess and other 
drift deposits. 
Prof. Chamberlin thinks the earth movements of elevation 
and depression were of less duration and less geographic ex- 
tent than would suffice for the accumulation of the ice-sheet : 
and all the drift formations in the Mississippi valley impl}- 
attitudes of the land either lower or not much higher than 
now. 
The Cenozoir history of eastern Virginia and Maryland. 
By N. H. Darton, Washington, D. C. In this paper, illustra- 
ted by a map and sections, the Lafayette formation and the 
two divisions of the Columbia formation in the neighborhood 
of Washington and Baltimore are referred to three stages of 
marine submergence on the coastal plain and estuarine condi- 
ditions in the river valleys, with intervening emergence and 
much erosion, greatest after the Lafayette epoch. 
Mr. McGee, in commenting on Mr. Darton'e paper, esti- 
mated the post-Lafayette erosion to average 250 feet over all 
that region of the coastal plain, while the post-Columbia eros- 
ion is comparatively very slight. The two stages of Columbia 
deposition are correlated with two glacial epochs in New Jer- 
sey, and the intervening emergence and erosion with an inter- 
glacial epoch at the north. 
Prof. J. A. Holmes and Prof. Salisbury also spoke of their 
