259 
of the undisputed St. Louis formations. But if this palezeontologic test is 
to be applied to the upper strata it is hard to understand how the Bed- 
ford odlitic can be retained as a member, as these fossils are not found 
in it. 
At the top of the sinkhole division of the St. Louis in Lawrence, 
Orange and Washington Counties, and doubtless in Harrison County, 
there is a constant stratum of chert from ten to twenty inches thick. 
Above this chert other thin flinty layers may be found, but so far as 
known, they are not fossiliferous. The heavy chert may be seen in place at 
Paoli in the north bank of Lick Creek, at the Wesley Chapel Gulf, and 
on Lost River near Orangeville. Because of its frequent occurrence on 
that stream is is suggested that it be named the Lost River chert. Itis gen- 
erally highly fossiliferous, very rich in bryozoans and occasionally odlitic. 
*Above, and conformable with it, there is found from sixty to ninety feet 
of massive, close-textured limestone, slightly broken at the top by beds 
of calcareous shale, and near the middle by included chert nodules; gen- 
erally the ground mass is lithographic. This stratum includes all the 
rocks found below the first Kaskaskia sandstone and above the Lost River 
chert, and as it is well exposed at that place it is proposed that it be 
known as the Paoli limestone. On paleeontologic grounds, which cannot 
be presented in full here, the Paoli limestone is assigned to the St. Louis 
group. The fossils that occur in it, at many places in abundance, are of 
the same species as the more common forms found at Spergen Hill. The 
chemical composition and general appearance is such as to clearly show 
that it is a repetition of the strata exposed below it. Its lithologic char- 
acteristics are obvious, and the residual clay resulting from its disintegra- 
tion presents the same physical appearance as the red, plastic and im- 
pervious clay of the undoubted St. Louis formations. 
Mr. C. HE. Siebenthal has proposed the name Mitchell limestone for “A 
series of impure limestones, calcareous shales and fossiliferous lime- 
stones” overlying the Bedford odlitic limestone, and says: ‘“‘The topo- 
graphic tendency of the Mitchell limestone expresses itself in plateaus per- 
forated at short intervals by sinkholes.’’* As he does not define the upper 
limits of his “Mitchell limestone” it is suggested that his definition be 
amended to include all the St. Louis limestone below the Lost River chert 
and above the Bedford o6litic. Its upper and middle strata are largely 
* Geol. Sur. Ind., 1896, pp. 298, 299. 
