Man in the Ice Age. — Uphani. 141 
the similar traces of man in early Quaternary sand and grave! 
deposits of the Somme and other valleys in France, attest man's 
existence there before the maximum stages of the uplift and of 
the Ice age. The acctimulation of the ice-sheets, due to snow- 
fall on their entire- areas, was attended by fluctuations of their 
gradually extending boiuidaries, givingthe Scanian and Xorf olk- 
ian stages, named by Geikie, in Europe, the Albertan formation 
of very early glacial' drift and accompanying gravels, described 
by Dawson, in Alberta and the Saskatchewan district of west- 
ern Canada, and an early glacial advance, recession, and re-ad- 
vance, in the region of the ^Moose and Albany rivers, soitthwest 
of Hudson bay. In that region, and westward on the Canadian 
plains to the Rockv mountains, there seem to have been thtts 
three stages recognizable in the glacial results of the epeiro- 
genic uplift, namely, the Albertan early ice accumulation, the 
later time represented by the Saskatchewan gravels, of abvm- 
dant glacial melting and extensive retreat, and afterward a vast 
growth of the continental icefields to their farthest limit, when 
they reached south to Kansas. The first recognized stage of 
glaciation in Xorth America is therefore called the Albertan 
stage. 
On the Atlantic coastal plain of the United States, south of 
the glacial drift, this stage is probably represented by the 
Lafayette formation ; and the subsequent deep fluvial erosion 
of the Lafayette beds I attribute to the very long ensuing 
Aftonian and Kansan stages. 
2. A deposit of glacial drift, the lowest and oldest observed 
in the Mississippi river basin, probably of Albertan age, stretch- 
es south at least to southern Iowa, where it is overlain by in- 
terglaciai beds, inclosing peat, well displayed in sections at 
Afton, Iowa. The Aftonian interglacial time, especially notable 
for its extensive buried forest bed, containing triniks of 
hardy northern coniferous trees, has been ascertained to be 
earlier than the Kansan readvance of glaciation. It is therefore 
probably equivalent with the Saskatchewan stage of Canada,, 
which name it should then displace according to the rule of 
priority. This second time division of the Glacial period, in- 
cluding a very important recession of the ice border, uncover- 
ing the ])reviously glaciated country as far north, probably, as 
