56 Notes upon the Geology of the Western States. 



stratified with the sandstone, and a few shells and corals are 

 found in them ; and whenever the thin layers of limestone dis- 

 appear, the same fossils are found in the sandstone. These char- 

 acters are distinctly seen near New Albany, in the hills known 

 as the Knobs, to the northwest of the village. 



Farther to the west and northwest, and above the sandstone 

 extending along the Ohio, on both sides, and into the states of 

 Illinois and Kentucky, there appears as a distinct and import- 

 ant mass, a limestone resembling that interstratified with the 

 sandstone just noticed. The lower part of this limestone is com- 

 pact, very fine grained, and some portions fit for lithographic 

 stones ; the upper part is coarser, often containing chert or horn- 

 stone, and finally the uppermost layers are oolite. It everywhere 

 contains the Pentremite and a peculiar coralline fossil, the Archi- 

 medes of Le Seur, besides Cyathophyllum and several shells of 

 the genera Terebratulaand Delthyris. On the Mississippi it con- 

 tains two or more species of Productus, a large Delthyris, and a 

 peculiar crinoidal fossil. In the oolitic portion, I saw a single 

 species of trilobite and a few small shells. This limestone can 

 be traced along the Ohio, upon both sides, almost uninterruptedly 

 as far as Leavenworth, fifty miles below New Albany ; it there 

 passes beneath the conglomerate, showing very clearly its posi- 

 tion in regard to the latter and the Chemung group. Beyond 

 this it does not uniformly appear ; the conglomerate, and in some 

 places, as at Hawesville, Ky., the coal formation coming to the 

 level of the river. It reappears again about Shawneetown in 

 Illinois, and is visible on one or both sides, almost continuously 

 to the mouth of the river. In ascending the Mississippi above 

 the mouth of the Ohio, it soon appears, forming cliffs which, be- 

 low St. Louis, attain the height of from one hundred and fifty to 

 two hundred and fifty feet above the level of the water. These 

 cliffs are turned to very important economical purposes ; small 

 buildings are erected upon the top, where lead is melted for shot 

 making ; the cliff serves the purpose of a high tower, the shot 

 being received below on the margin of the river. This limestone 

 extends along the Mississippi to near the mouth of Rock river. 



We have then throughout all this great extent of country, from 

 central Indiana to beyond the Mississippi river, a limestone dif- 

 fering entirely in all its most essential characters, and emphat- 

 ically in its position, from any in New York. Among its fossils 



