i Geological Padi on the éhibpis Land Disiriet 
nian system of the Hifel, if not identical with it. Hinds strata 
appear to be the equivalent of the rocks described in my report 
of 1839, as occurring lower down on the same stream in the Du-. | 
buque district, so that the line of bearing between these two form-  - 
ations, Silurian and Devonian, seems to run nearly: Barallel. with: 
that stream a 
“The Red Cedar limestone pies up its west ivnch as far as. 3 
I penetrated, i.e., to near the north line of the Winnebago’ Re- | 
serve ; it also stretches away si “the west as far as the limits-of » 
my observations, viz.: to Willow river. On Shell Rock, the 
east branch of Otter, I found i in it, besides Atrypa prisca, casts of — 
Lucina proavia, and an undetermined species of Leptena. But. 
the fossil which is most abundant, and most universally distribu- 
ted through the rocks of this western portion of t inne ebago 
Reserve, is a very fine structured coral, composed of concentric 
layers, like the genus Stromatopora, but so close together that 
aS 
Jong 
. eae 
strata are so full of this close grained coral that it might with. 
propriety be called a coralloid limestone. 
‘ee * ** Some of the beds of this formation consist of very close tex- 
tured and smooth calcareous beds, like the lithographic limestones, 
splitting with a flat conchoidal fracture. In it I did not observe 
any fossils; but I had not many Ducat nia of examining ex- 
posures either of it, or, indeed, of any of the other members of 
the formation in question, along the line of my route. The geol-— | 
ogist who undertakes to investigate the vast prairie countries of 
the Mississippi valley must be provided with no common share of © 
patience aud perseverafice. He must be content to travel for. ~. 
half a day together without seeing aught but a rich black soil, 
covered, as far as the eye can reach, even down to the very edge 
of the small streams, with a thick and high growth of prairie 
grass, with, perhaps, a faint outline of timber cutting the distant - 
horizon. He must be prepared to wade swamps, to ‘ford streams 
waist deep, or, in times of freshets, to plunge in and breast the . 
current. He must not shrink beneath a broiling sun, without —~ 
* even a bush to cast a faint shadow over an occasional resting place. __ 
He must think himself fortunate, if he can reach, at night, afew _ 
“scattered oaks to plenish his fire, and boil his camp-kettle ; and" — 
the may consider it a special inieenes of good luck, if, in return, 
he can catch a glimpse of a rock exposure once or twice a day. . 
He may travel for days together without lighting on any object » 
more interesting than the hillock of the prairie dog, or the broad 
lair of the bison.”—pp. 36, 37 
_._ The western portion of the Reserve is said to present no indi- = | 
_ ¢ation of being a mineral country. Some portions of the ey 
river — Upper Iowa country afford a ~ lead ore. 
eee ee 
