H4 The American Geologist. August, 1903 
clay described by Chamberlin, as before quoted, is not an or- 
dinary lacustrine sediment, in the sense of being- brought by 
tributary streams or supplied through erosion from the shores 
and bed of the old lake by its wave action, but rather that this 
deposit consists of englacial drift which here was received in- 
to the water of the glacial lake. By lacustrine action it was 
somewhat stratified and assorted, but, by its inclusion of fre- 
quent rock fragments, it yet retains generally, as I think, more 
of the features of till than it has acquired of the usual charac- 
ters of water-laid drift. 
The purpose of this paper does not include a discussion of 
the relation of lake Xicolet to lakes Cbicago and Duluth, which 
can only be learned by much field work, with exact mapping 
of the old shore lines and determination of their bights by 
leveling. It seems sufficient here to add that, if lake Chicago 
at any time fell below the Chicago outlet, it must, in my opin- 
ion, have then outflowed by the way of Portage to the Wis- 
consin river. 
An exceptional uplift of the region about Portage, the 
upper Fox river, and lake Winnebago, exceeding that of the 
surrounding country, may well have taken place between the 
times of formation of the first and second of the lake Chicago 
beaches, giving to this area of lake Xicolet the altitude which 
it has since held, or perhaps slightly more. Indeed, the uplift 
seems to have been followed by some depression there, or at 
least about Green bay, while the country northward, including 
the basin of lake Superior, was being elevated. 
The complex and very interesting history of the departure 
of the ice-sheet from the St. Lawrence basin, the Sequence and 
changes of its immense ice-dammed lakes, and the variable 
northward uplift of the country during that geologically short 
Champlain epoch, continuing in less degree to the present time, 
I somewhat fully reviewed about eight years ago.* The opin- 
ion then expressed seems to me still to be true, that, after lake 
Chicago (since that time so named by Leverett) and lake 
Duluth (since named by Taylor) became confluent, their suc- 
cessor, lake Warren | named and well described before that 
* Amer. Jour. Sci., third series, vol. xlix, pp. 1-18, with map, Jan., 1895; 
Twenty-third Annual Report, Minnesota Geol.and Xat. Hist. Survey, for 1S94- 
(pub. 1895), pp. 156-193, with map. This paper contains very fall bibliograph- 
ic citations of all previous writers on the glacial lakes of the St. Lawrence 
basin. 
