284 The American Geolof/ist. May, 1895 
period or to have liad far more favorable conditions for stream 
erosion. 
Soufho-n Illinois, hnliinui, and Ohio. — The earliest records 
of observations of interglaeial forest beds in Ohio and other 
states farther west were made thirty years ago by Whittlesey ; 
and the reports of the several state geological surveys since 
published contain plentiful notes of the occurrence of these 
beds between deposits of till, summaries of which have been 
included b}' several authors in their discussions of the drift.* 
The most recent of these discussions is by Leverett, who has 
traced a large series of marginal moraines through these 
states. His paper, accompanied by a map of the moraines in 
eastern Indiana and western Ohio, enumerates the glacial and 
interglaeial stages in their order as follows. 
1. A glacial stage during which the ice-slieet extended farther South 
in this region than in any later stage. 
2. A long stage of deglaciation marked by development of soil and by 
attendant oxidation, leaching, and erosion of the drift. 
3. A stage of silt deposition during which the highest points in south- 
western Ohio apparently became covered at flood stages. The region 
then stood probably several hundred feet lower than now. From evi- 
dence gathered farther west, the sill deposition seems to have accom- 
panied a glacial stage whose deposits are concealed in this region by 
later drift sheets. 
4. A glacial stage, during which the outermost well-defined frontal 
moraine was formed, with as good attendant drainage as is now afforded 
in the western Ohio region. The drift of this stage is concealed in 
eastern Ohio by the later moraines. The main streams at the time of 
this glaciation flowed at levels 200 feet or more below the level of the 
upland silt. 
.'). A stage of deglaciation of considerable length, with altitude some- 
what as at present, indicated by valley exca\'ation. 
G. A glacial stage characterized by sharply indented morainic ridges, 
with such elevation and slopes of th(' land as to give more vigorous 
drainage than now, not only in Ohio, but as far to the west as the mo- 
raine has been correlated. The ice-sheet reached about to the glacial 
boundary in eastern Ohio, but fell short many miles of reaching the 
boundary farther west. 
^Charles 'Whitllesev, Smithsonian Contributions, oS'o. 197, vol. xv, 
18G4, pp. 1;M5. 
J. S. Newberry, Geology of Ohio, vol. ii, 1874, pp. D0-B3. 
N. H. AVinchell, Proc. Am. Assoc, for Adv. of Science, vol. xxiv. for 
1875, Part ii, pp. 4:5-50. 
G. F. AVright, The Ice Age in North America, 1880, pp. 475-49(3. 
Frank Lev(>rett, Journal of Geologv, vol. i, pp. 129-140, with map, 
Feb.-March. 1893. 
