2... of Wisconsin and part of Iowa. oe. 
: there are als. isolated, mound-like hills, nearly flat on the top and 
*)-* so. symmetrical in form that, were it not for their height and extent 
_ and their being composed in their interior of solid ledges of rock, 
> one might be tempted to attribute to them an artificial origin. 
4 + The lower. strata are more schistose, being chiefly marlites with 
‘alternations of calcareous layers. e€ most conspicuous fossils 
are: Leptena Madisoniensis, L. sericea, L. alternata, Orthis 
.. formosa, Pleurotomaria bilex, and Isotelus megistos. Others less 
*. abundant, are: Alrypa capaz, A. exigua, Spirifer lynx, Trochus | 
ee Lage Several trilobites probably of undescribed species allied to 
the rock exposure near the confluence of that stream with the 
Mississippi. — 
'. There are many fine examples on this river of those remarka- 
ble castellated forms which the lower as well as upper magnesian 
_. limestone often assumes. Several sketches illustrating the fea- 
tures of the country, accompany the report. 
_On the Upper Iowa, about longitude 91° 50’, the following fos- 
sils were found in the lower 150 feet of rock: Leptena sericea, 
tena rugosa, L. Madisoniensis, L. deltoidea, L. alternata, 
Pleurotomaria lenticularis, Cyathophyllum ceratites, Coscinopora 
suleata, Bellerophon bilobatus, Isotelus megistos, Orthis testudi- 
naria ? O. formosa, Illenus crassicauda, Murchisonia belli- 
- etnctu, M. subfusiformis, Atrypa capax, Orthis subequata, 
Atrypa hemiplicata, Orbitulites? reticulatus ? ? 
In this part of the Reserve the formation is evidently of the 
‘Same age as that near the Agency on Turkey river, which lies 
eee wranty miles to the south. Both appear to represent the 
Hong the Red Cedar river we extract the following : iF 
“On Red Cedar there is a change in the geological formation — 
fthe country. Either this is the western limit of the formations 
- of Upper Iowa and Turkey rivers, or else the southwest dip car- 
lies the formations before reaching the Red Cedar beneath the _ 
water courses; for on crossing the Red Cedar, the first ledges that — 
under my observation, only a few hundred yards to the 
of it, were found to be charged with the large variety of 
prisca and a Spirifer, very abundant in the shell beds of — 
the Ohio, and allied to the S. ostiolata of the Devo- 
mies, Vol. X, No. 28.—July, 1850, 2 igi 
