178 [May, 1S42. 



upper, particularly the water lime, has also many of the Ludlow. The lower and 

 middle portions of the Cliff limestone, he conjectures to be equivalents of the Ni- 

 agara limestone and Gypseous shales : the entire mass called the Cliff limestone, 

 represents therefore the Niagara limestone, Gypseous shales, water-lime, Ononda- 

 ga limestone, &c. to the Marcellus shales. Under the name Cliff limestone is 

 here included all the group above the blue limestone and marls of Cincinnati, to 

 the black slate. It is the western continuation of the middle Silurian series of 

 Mr. Conrad. 



The water-lime of the Falls of the Ohio, is a drab-coloured rock, from ten to 

 fourteen feet thick, covered by a subcrystalline foetid limestone eight feet thick, 

 containing Enerini, a Conu/aria, Delthyris and Favosites, and a few other co- 

 rals, and immediately underlies the black slate. In mast places the water-lime is 

 entirely destitute of organic remains ; the few which occur belong to the lower 

 Ludlow and Amestry of Murchison, as Orthis hmata vel reticularis, leptxna 

 lata ? Turbo carinatus, Terebra sinuosa, Tentaculites, perhaps a new species, 

 Avicula reticulata, Calymene bufo, Aaaphus Micrurus; several undetermined 

 species of Delthyris, an Eschara, &c. 



In the strata below the water-lime were f mnd many fossils of the Wenlock 

 limestone, Strophomena euglypha, Atrypa prisca, the latter also occurring in 

 the water-lime and upper limestone; Pleurorynchtts cureous? of Conrad, and 

 an immense profusion of Polyparia, characteristic of the Wenlock limestone. 



The Catamepora occurs below the main mass of the corals, and thirty or forty 

 feet below the water-lime. It would therefore appear, that the water-lime belongs 

 to the middle or upper part of the Hederburg group, and cannot represent the 

 Onondaga salt group of Mr. Hall. 



The author expresses a doubt of the identity of the black bituminous slate of 

 Ohio, with the Ludlowville group of Mr. Hall, as supposed by that gentleman. 

 Though the shales and sandstone in the vicinity of New Albany, for more than 

 four hundred feet above the black slate, are destitute of fossils, except a few in- 

 distinct Fucoides, yet sixteen miles south, in Kentucky, great quantities of Cri- 

 noidiea occur, fifty or one hundred feet above the slate; and an Orthis which 

 Mr. Hall consideis identical with a species of the Ludlowville shale of New York. 



ELECTION. 



M. Leon Dufour, of Paris, was duly elected a correspondent 

 of the Academy. 



