‘240 The American Naturalist. — [March, 
rapidly ; its chief stage of loess deposition attended the early 
part of this glacial retreat; the partially unburdened land 
began to rise by a moderate uplift, approximately proportion- 
al to the glacial melting and nearly keeping pace with it ;" and 
conspicuous belts of morainic drift were amassed whenever 
the steep waning ice-front slackened its departure, or halted, 
or for any short time reidvanced. The general but fluctuat- 
ing retreat of the ice-sheet at length uncovered all the country 
and constituted the closing or Champlain epoch of the Ice age, 
so named from the marine beds of that time overlying the till 
in the basin of lake Champlain and along the St. Lawrence and 
Ottawa valleys, by which the vertical extent of the subsidence 
terminating the Glacial period and of the succeeding reéleva- 
tion is measured. ; 
Adopting the helpful new nomenclature proposed by 
Chamberlin,” we may provisionally formulate the minor time 
divisions of the Glacial and Champlain epochs as follows. The 
order of this table, as of the former more comprehensive one 
on page 988 of the last December AMERICAN NATURALIST, iS 
stratigraphic, so that for the advancing sequence in time it 
should be read upward. 
Nore.—If we seek to compare this table with the Glacial series in Europe, it 
should be remarked that in the Alps there were three chief stages of growth of 
the glaciers far beyond their present limits, the second being the maximum 
advance, doubtless contemporaneous, as shown by Geikie, with the maximum 
extension of the ice-sheet upon northern Europe. The first glacial stage of the 
Alps, which also appears to have left traces in southern Sweden not wholly 
obliterated by the next and greater glaciation, may be represented in America by 
the till beneath the interglacial lignite in the basin of James bay, and these may 
belong to the time of northern winters in aphelion some 50,000 years ago. The 
second, third, and fourth glacial stages of the European Ice age, as tabulated 
by Geikie, are then seen to be wholly analogous in characteristics of ice extension 
and drift deposition, and they were probably also time equivalents, respectively, 
with the Kansan, Iowa, and Wisconsin stages in the United States and Canada. 
In each continent the interglacial time between the Kansan and Iowan stages had 
" Journal of Geology, vol. ii, pp. 383--395, May-June, 1894. 
12 In two chapters (pages 724-775, with maps forming plates xiv and xv) of J. 
Geikie’s “The Great Ice Age,” third edition, 1894, Prof. T. C. Chamberlin pro- 
poses a chronologic classification of the North American drift under three forma- 
tions, named in the order of their age, beginning with the earliest, the Kansan, 
East Iowan, and East Wisconsin formations. 
