Contributions to Invertebrate Palseontology. SSt 



to pass below the " Bone-bed" are very few. These, with the ex- 

 ception of the Tentacidites scalariforviis, have been illustrated on 

 Plate VII, and are, with two exceptions, known Marcellus and 

 Hamilton types, one being a new species, and the other (Spirifera 

 Ilaia Bill.), occurring in the Upper Helderberg- limestone in Canada. 

 The examination of the upper layers for characteristic fossils was 

 not carried far enough to make it perfect, owing to Mr. Hyatt's 

 absence from Columbus; but the few forms found above these bitu- 

 minous layers will readily be recognized as characteristic of the 

 Hamilton group, and warrant one in considering the Black shales 

 and other beds coming above these thin limestones in central Ohio, 

 as equivalent to the Genesee slates and succeeding formations of 

 New York.^ 



The following lists, prepared by E. and H. Hyatt, of Columbus, 

 Ohio, are from the limestones within 24 miles of that place. Those 

 of the first list are from below the horizon of the " Bone-bed," and 

 the next from above ; Strophomena rhomboidalis being the only 

 species fully recognized from both horizons. All species have been 

 collected by them from known horizons, or have been seen from the 

 beds by myself. 



5 Since writing the above remarks, Vol. V of the Palffiont. of New York has 

 been published. In it the author has, on p. 139, some remarks on the lime- 

 stones at the Falls of the Ohio, and their relations to the Hamilton group of 

 New York. After showing that the Hydraulic-cement beds of the Falls of the 

 Ohio are the equivalents of the Hamilton group of New York (which had already 

 been stated in the Geol. Rept. Ind., 1875, pp. 147, 148, and also shown in sec- 

 tions on page 157), the author remarks, " In the State of Ohio, similar condi- 

 tions may be inferred, from the fact that certain known species of Hamilton 

 fossils are published in the Ohio Geological Reports as from the Corniferous 

 group." At the meeting of the Am. Assoc, for the Advancement of Science, at 

 Saratoga, August, 1879 (see Proc. A. A. A. Sci., vol. xxviii, p. 297), I read a 

 notice of the occurrence in Ohio of rocks representing the Marcellus shales of 

 New York, embracing most of the substance of this note, and in which it was 

 shown that a considerable thickness of the limestones previously recognized as 

 " Corniferous" in Ohio, were above the horizon of the beds which I had recog- 

 nized, from palfeontological and lithological evidence, as of the age of the 

 Marcellus sliale, and would be of necessity equivalents of the Hamilton group. 

 This was in August, 1879. The volume above-mentioned is dated, in the letter 

 of transmissal, Dec. 15, 1879. 



Annals N. Y. Acad. Sci., V, Dec. 1890.— 36 



