* 
: 
7 
: 
3 
a 
a 
Z * 
E. Andrews on the Western Boulder Drift. 173 
—— supposed to be of the same age, lies on the south shore 
5 
ake Huron ; and others have been struck by sinking wells at 
several places both in the northern States and in Canada. An-~ 
other fact is of considerable interest, as showing how closel 
the succession of Quaternary formations here follows the rela~ 
tions in Kurope, as shown by Mons. Dupont in Belgium, Upon 
the top of the glacial drift, and separating it from the loess 
there is another dirt bed, which has been studied mainly at 
Davenport, Iowa, by the Davenport Academy of Sciences, It 
appears that at the close of the glacial drift in that region, the 
waters of the Mississippi subsided within the rock bluffs, and 
the drift slopes were covered with soil, which showed its atmos- 
pheric exposure by the fact that it was guttered to some depth 
by small streams which cut perpendicularly into it. Over this 
soil lies the loess often forty feet in depth, The same forma- 
tion apparently is exposed at Quincy, Ill., and traces of it are 
seen in other parts of the west. It appears therefore that the 
fresh-water submergence which deposited the loess was not a 
continuation of the drift action, but was in this region separated 
from it by a tranquil period, during which the rivers were down 
within their banks, and at or near their present levels. The 
loess at Davenport a short distance above the dirt bed, yielded 
the skeleton of an Elephas, probably americanus. The shells 
e 
found there were all land species so far as yet discovered. The 
following comparison shows how closely Quaternary events in 
_ the Mississippi valley have kept step with those in Europe. 
European Section, : 
(from Dupont’s Belgian Excavations.) 
Present soil. Present soil 
Loess. Extensive submergence. ss. Extensive submergence. Terre a 
brique of Belgium and France. 
Ancient soil, worn by aerial denudation-|Ancient soil and land surface. | ns 
Streams within their banks. Great) within their banks. Middle river drift 
Pachyderms alive. Human relics re-| of Belgium and France. Great achy- 
ported but not established. derms apparently existing. Paleolithic 
sca 2b human relics 
Glacial Drift. Rolled stones and boul- Lower river drift of Belgium and France. 
‘ers derived from the north. No fo ed stones and large boulders trans- 
sils either human or otherwise. Great rom a distance, in the direction 
ion, of the river valleys. No human relics. 
Pachyderm bones abundant. Evidences 
of ice action. 
American Section. 
Pre-glacial soil, probably Pliocene. Fau-|Pre-glacial soil seen at Norfolk Crag. (Ly- 
t explored. ell.) 
_ Another characteristic of western drift is that as a whole 
it is beyond all question a stratified water deposit. There is 
probably in no part of the world so good an opportunity to set- 
tle this disputed point by field observation. The waves of the 
. great lakes eroding their shores keep exposed hundreds of miles 
oe 
