2 54 The Aniericaii Geologist. October, ii98 
now at a much lower altitude than the original mountainous water- 
shed. 
In the session of the National Geographic Society with Section E, 
the following papers were presented: 
1. The Venezuela-British-Guiana Boundary Dispute. By Dr. 
Marcus Baker, Washington, D. C. 
2. Considerations Governing Recent Movements or Population. 
By John Hyde. Washington, D. C. 
3. Some New Lines of Work in Government Forestry. By 
GiFFORD PiNCHOT, Washington, D. C. 
4. The Development of the United States. By W J McGee, 
Washington, D. C. 
5. Atlantic Estuarine Tides. By M. S. W. Jefferson. 
6. The Forestry Conditions of Washington State. By Henry 
Gannett, Washington, D. C. 
7. The Five Civilized Tribes and the Topographic Survey of In- 
dian Territory. By Charles H. Fitch, Washington, D. C. 
8. Bitter Root Forest Reserve. By Richard U. Goode, 
Washington, D. C. 
It is expected that several of these papers will be published in the 
National Geographic Magazine. 
The papers of Section E were as follows: 
1. Outline Map of the Geology of Southern New England. By 
Prof. B. K. Emerson, Amherst, Mass. This paper, with maps, gave 
a summary of the areal geology of Massachusetts, Rhode Island, Con- 
necticut, and parts of New Hampshire, Vermont and New York. 
2. Basins in Glacial Lake Deltas. By Prof. H. L. Fairchild, 
Rochester, N. Y. During the glacial recession, the impounded high 
waters of the Canandaigua valley, in central New York, at one time 
escaped across the eastern border of the basin into the Flint creek 
valley, which was also occupied by a glacial lake at a lower level. The 
river thus formed cut a channel in drift and rock, and deposited the 
aebris, as a delta, at its mouth in the lower lake. The delta now 
forms a conspicuous plateau of gravel 125 above the village of 
Potter. In this plateau is an irregular depression which reaches to 
the very base of the delta deposit, and occupies perhaps one-fourth of 
the area of the plateau. The only satisfactory explanation of its origin 
is that an isolated block of ice was left here by the receding ice-front, 
and that the delta material was piled around it, the subsequent melting 
of the ice block producing the cavity. Elsewhere shallow basins oc- 
curring in deltas are in many cases attributable to deficient filling by 
capricious currents and wave action; but such bowls cannot be con- 
founded with the Potter kettle-hole, whichwas illustrated by a map 
and photographs. 
