274 The American Geologist. May, 1895 
layers of peat and lignite, are reported by Dr. G. M. Dawson, 
Dr. Robert Bell, and others of the Canadian Geological Sur- 
vey, from the Pacific coast in British Columbia, the Saskatch- 
ewan plains, and the country bordering the southwest side of 
Hudson and James bays. On the north shore of lake Ontario, 
at Toronto and Searboro, very interesting fossiliferous inter- 
glacial deposits are described by Hinde and Coleman. In the 
United States they are chiefly confined to the upper Missis- 
sippi basin, the principal phase of their development being 
the well known "forest beds'' of the drift series in Ohio, In- 
diana, Illinois, Iowa, and southeastern Minnesota. 
In these states an important oscillation of the ice-border 
took place after the formation of the early Kansan member of 
the Mississippi drift series.* From the Kansan stage of max- 
iiiium area of the ice-sheet, it was melted back j^robably to 
the northern limits of the forest beds in the upper Missis- 
sippi region. During the ensuing lowan stage of reiidvan- 
cing glaciation, increased snowfall and ice accumulation, with 
inflow of ice bringing drift from the north, overspread these 
interglacial forests, which had grown up to the border of the 
previously retreating ice, if not indeed upon its drift-covered 
margin, as now on that of the Malaspina glacier or ice-sheet. 
During all the glacial recession, interrupted after the be- 
ginning of the moraine-forming or Wisconsin stage, when the 
ice boundary (numbered 2 on plate X) was at the Altamont 
or first moraine, by many pauses and slight readvances, which 
are marked by the knolly and hilly moraine belts, trees, 
shrubs, and herbaceous plants likewise probably grew close 
to the ice-front and may here and there have become covered 
bj'^ the late Wisconsin till and moraines, as during the more 
extended lowan oscillation of the ice boundary. Mainly, 
however, the glacial fluctuations or pauses or slackening in 
the rate of retreat, whereby the moraines were amassed, ap- 
pear not to have been sutflsient for the envelopment of fossil- 
iferous beds by overlying till or morainic drift. A most 
*ln two chapters (pagos 724-775, with maps forming plates xiv and 
XV) of J. Geikie's "The Great Ice Age," tliird edition, 1S!M, Prof. T. C. 
Chambei'lin proposes a chronologic classification of the North American 
drift under three lormations, named in the order of their ag(\ beginning 
with the earliest, the Kansan, East-Iowan, and East-Wisconsin forma- 
tions. 
