174 



The Hydraulic Beds, etc., 



of the State of New York, I became doubtful of the real 

 identity of the higher beds with the !N"ew York limestoues ; 

 and in considering the numerous species of characteristic 

 Hamilton fossils which they contain, I became satisfied 

 that there was yoom for farther inquiry and comparison. 



In the rnonth of August of the present year (1877), dur- 

 ing a low stage of the water in the river, I had an op- 

 portunity of examining the waterlime and superincumbent 

 beds, as well as the coral-bearing beds beneath. 



A considerable portion of the waterlime beds consists 

 of an argillaceo-magnesian limestone, destitute of organic 

 remains. The upper part contains many specimens of 

 Spirifera euruteines, and the thinly-bedded, slaty and sili- 

 ceous strata above it are charged with numerous fossil 

 species, the most abundant of which is the Chonetes Yan- 

 dellana ; but many other known forms occur, and the en- 

 tire facies, when critically viewed, presents the general 

 aspect of the fauna of the Hamilton group. The encrin- 

 ital bed above these thin layers contains numerous Crin- 

 oidea, all of which are congeneric with Hamilton forms, 

 and many of the species are identical with those known 

 in that horizon in the state of ]N"ew York. 



The following tabulated list of species from the Devon- 

 ian limestones at the Falls of the Ohio, though incomplete, 

 will serve for a comparison with the Upper Helderberg 

 and Hamilton groups of New York. The species indicated 

 in the first column are known species of the Upper Hel- 

 derbers: limestones of New York,^ and occur at the Falls 

 of the Ohio in beds u, v and iv of Major Lyon's series 

 (p. 173). All the species which pass upward into the suc- 

 ceeding hydraulic and encrinital limestones are likewise 

 known to pass from the limestones below into the Hamil- 



^ Pleurotomaria imitator, Turbo Shumardii and Dalmanites Calypso, 

 have not yet been observed in this formation in the state of New York. 



