294 The American. Geologist. 
May, 1895 
sion of the falls of St. Anthony for the Postglacial or Recent 
period.* and with his estimate of the duration of the inter- 
glacial stage from the now buried channel which appears to 
have been then eroded by the Mississippi river a few miles 
west of the present gorge below these falls. f 
Next ensued, initiating the second and shorter final epoch 
of this period, a widely extended depression of the ice-bur- 
dened land, until mostly it had somewhat less altitude than 
now. Temperate and warm climatic conditions on the ice 
border, nearly as now on the same latitudes, then melted away 
the ice rapidly; its till and loess were deposited in the reces- 
sion from the lowan stage; the partially unburdened land 
began to rise by a moderate uplift, approximately propor- 
tional to the glacial melting and nearly keeping pace with it; 
and conspicuous belts of morainic drift were amassed when- 
ever the steep waning ice-front slackened its departure, or 
halted, or for any short time readvanced. This general but 
fluctuating retreat of the ice-sheet, constituting the Wiscon- 
sin stage, divisible into minor stages as shown in plate X, un- 
covered all the country and was the closing or Champlain 
epoch of the Ice age, so named from the marine beds in the 
basin of lake Champlain and along the St. Lawrence and Ot- 
tawa valleys, by which the vertical extent of the subsidence 
terminating the Glacial period and of the succeeding reeleva- 
tion is measured. 
The following table, from my recent discussion of the time 
divisions of the Quaternary era, J shows the relation of the 
Glacial period to the earlier and later parts of this era, the 
arrangement being in the descending stratigraphic order of 
their geologic formations. 
Periods and JSpochs of Quaternary Time. 
T^ < D ^ »™.,^x.,„^ 5 Recent or Present epoch. 
PsYCHOZOic DIVISION | RECENT PERIOD j Terrace epoch: 
r /^ .„. ., „. < Champlain epoch. 
r Glacial PERIOD \ Glacial epoch. 
-' ( Epoch of great e 
Lafayette PERIOD. .. j sion. 
l^ f Lafayette epoch. 
Pleistocene DIVISION -{ , ( Epoch of great elevation and ero- 
1 Lafayette PERIOD. .. i sion. 
*Geol. and Nat. Hist. Survey of Minnesota, Fifth An. Rep., for 187G, 
pp. 175-189: Final Report, vol. ii, 1888, pp. 313-341, with fifteen plates 
(views showing recent changes of the falls of St. Anthony, and maps). 
Quart. Jour. Gleol. Soc, London, vol. xxxiv, 1878, pp. 880-901. 
fAM. Geologist, vol. x, pp. 09-80. with three plates (sections and a 
map), Aug., 1892. 
tAm. Naturalist, vol. xxviii, pp. 979-988, Dec, 1894. 
