Dt'i'iiKj the (rlac/al J\riod. — Claiinherlln. l27l 
drift. It is worthy of note that these trenches are cut throngh 
the older moraines and their overwasli aprons of silt and are sunk 
down into them or l)el()w them. The later gravel-bearing Hoods 
ran at lower levels than the earlier silt-bearing waters: a clear 
demonstration of a change of attitude. It is clear from a study 
of these phenomena that at the time this moraine was formed the 
action of the ice was more forcible and the drainage more 
vigoroixs. The glacial waters ran away from the whole margin of 
the ice with measureable precipitancy, bearing coarse material. 
They gathered into definite channels previously cut in tlie older 
drift and ran along these at a rate which enaliled them to carry 
gravel and sand far down their courses. Here we have for the 
first time in the history of glaciation. so far as now worked out 
on this the most favoral)le line on the continent for such study, an 
indication of an altitude and sloj)e of the surface sufficient to })ro- 
duce vigorous drainage. 
The question now becomes jjertinent. how vigorous? How 
great a slope was indicated? On the Illinois river. o\er\vasli 
was sufficiently strong to spread out. on the outer side of the 
moraine, plains of gravel and sand of moderate degree of coarseness. 
Immediately next the moraine col)ble stones of three inches in 
diameter are not uncommon. J^ut only a few miles away from 
the moraine, even in the nuiin axis of the gravel stream, tlie 
uuiterial l)ecomes predomiiuuitly sand, the gravel l)ecoming fine 
and snl (ordinate. Near Chillicothe. for reasons not well under- 
stood, the material is again coarse but beyond l)ecomes chiefly 
sand. On the Wab:isli similar facts present thi'inselves. 
Within two or three miles of the moraine the deposit is chiefiy 
fine gravel and sand and maintains this constitution far down the 
stream. 
If 1 have correlated the mcuaines correctly, phenomena of the 
same kind and occuring at the sanu' date are found on the Hock 
river, starting aliout twenty miles north of the Wisconsin line neai' 
-lanesville; on the Wisconsin river in Sauk county. Wis.. l)i'i()w 
its great l)end: on the Chippewa river a few miles above (Miippewa 
Falls: on the St. Croix river a few mih's al)o\c its inoutli; on tlie 
.Mississippi river a short distance liclow St. Paul: and on the |)es 
>Ioines river, at the city of l)i's .Moines. Similiar phenonuMui also 
occur on all of the important ti'iliutaries of the Ohio and the .\lle- 
iihenv from eastern Inditina to iiortliwcstern l'eiiiis\ l\ ;ini;i. in all 
