120 GEOLOGY OF ILLINOIS. 



No. 4 thicker by five feet. Here, it also is divided into two strata, each four 

 feet thick, not differing lithologically, but with a very distinct line of separa- 

 tion. At this place, I obtained from bed No. 4, in addition to the species col- 

 lected at the other locality, Galymene Ittumenbachu, Pentamerus oblongus, a 

 Comulites, and some additional corals. The quarry in the village of St. 

 Charles, on the western side of the river, may perhaps be in another bed than 

 those exposed here, as the stone seems slightly different; it, however, resembles 

 No. 1, rather than the others, and is possibly identical with that bed. 



At St. Charles, the rock disappears under the surface, and no exposures are 

 met with, up the river, for nearly four miles. At this distance from the vil- 

 lage, however, a slight undulation of the strata, or a low anticlinal, brings it 

 again to the surface, and it is prominent, in perpendicular ledges and cliffs of 

 low elevation for nearly a mile along the western bank of the river, and for a 

 less distance on the eastern side. The exposures of the rocks of this group 

 here consists of about twenty-five feet of the lowermost beds, resting immedi- 

 ately on the shales and shaly limestones of the Cincinnati group. The slope 

 here is very slight each way, and indeed, but for the fact of the underlying 

 beds of the Cincinnati group being brought to the surface, the disturbance of 

 the strata would be hardly noticeable. The rock consists of intercalated beds 

 of light gray limestone and buff colored dolomite, containing in the lower por- 

 tion a few thin seams of chert. The light gray portions of the rock answer 

 well for burning into quick lime, and some of the other beds seem to be suitable 

 for the manufacture of cement. The axis of the disturbance is crossed by the 

 road at Mr. Jucket's lime kiln, in the southwest corner of section 3, township 

 40, range 8 east, and its trend is about northwest and southeast. The Fox 

 river is diverted from its course by this obstruction, and runs in a northwesterly 

 direction along its northeasterly edge for about a mile, breaking through it 

 and running again to the southward, in the southwestern part of section 3, 

 township 40, range 8. But few fossils were obtained in the bed of the Niagara 

 group at this locality, only Stromatopora concentrica, a Favosites, an lllajnus, 

 together with a few imperfect casts of gasterapod shells, and some indetermin- 

 ate corals, being found. 



North of this disturbance, exposures are also wanting along the river till the 

 village of Clintonville, distant between two and three miles, is reached, where 

 the rocks once more come to the surface. In the quarry here, on the western 

 side of the river, a little above the village, in the southwest quarter of section 

 26, township 41, range 8, the same strata and order of superposition are ob- 

 served as at Cedar Bluffs, below St. Charles, with the exception of the upper 

 part of No. 1, only about ten feet of which is exposed. The thin shaly seam, 

 No. 2, is also much thinner, having here a thickness of not more than five 

 inches, and about three feet in thickness, immediately below, represent No. 3. 



