1881.] The Loess in Central Towa. 783 
The occurrence of the loess in extensive outcrops, Over areas 
subjected at a previous time to geological 
investigation, but of which no mention is made, 
and that, too, in Central Iowa, was wholly 
unexpected. The formation was first seen, 
and its true nature surmised, at a point some 
two and one-half miles west of the city of Des 
Moines, on a branch cut of the C. R. I. & P. 
R.R. The cutting was made in the course 
of building a branch to the State Fair 
Grounds, in the summer of 1880, but the 
nature and true geological age of the material 
through which it passed seems to have re- 
mained wholly unknown. Subsequently out- 
crops were seen and studied at various places 
in and around the city, and specimens of the 
soil, the characteristic concretions and fossils, 
were taken from them all. Some of these 
exposures, owing to recent excavations like 
those in process of completion on Capitol 
Hill, in East Des Moines, show the deposit to 
be very extensive, and indicate that the higher 
lands, for some distance to the east and west 
of the Des Moines river in this locality, are 
composed in great part of true loess. 
Fig. 1 is representative of an actual section, 
as it may be seen at a point some three and 
one half miles above the city of Des Moines, 
on the river of that name. It will be seen 
from this section that the loess forms the bluff 
Or face of the third terrace, and probably forms 
€ mass of the higher land in the imme- 
diate vicinity of the stream. Beneath the 
loess is found the drift, and beneath that again 
the clays of the coal measures. The river has 
cut its channel, by corrasion, through the for- 
Mations mentioned, and in some localities has 
roded a channel through the sandstones 
found beneath the clays. Geologists will be 
able to form their own conclusions from these 
data, and see in them, perhaps, some of the 
"BMOT ‘SOULOJ SACT JO AjID OY} DAO" ‘I9ALI SAUTOY| Sac] sso1ov UOTDIS—'I “OL 
Avy ‘b fyup ‘€ {ssaoy ‘e faovssay ‘1 
