FOSSILS OF THE NIAGARA GROUP. 305 



[Originally printed in advance, for the 18th Report on the New- York Staie Cabinet.] 



Albany, December 26, 1864. 



XIX. ACCOUNT OF SOME NEW OR LITTLE KNOWN SPECIES OF 

 FOSSILS FROM ROCKS OF THE AGE OF THE NIAGARA GROUP. 



BY JAMES HALL. 



GEOLOGIST OF THE STATE OF NEW-YORK. 



I. RELATinNS OF THE NIAGARA GROUP WITH THE LECLAIRE AND RACINE 

 LiMESTOi\ES OF IOWA AND WISCONSIN, AND THE 6ALT OR GUELPH LIME- 

 STONE OF CANADA WEST. 



In the study of the fossils of the Niagara group and associated strata, 

 previous to the publication of the final report on the Fourth Geological 

 District,* and also to the publication of the second volume of the Palaeon- 

 tology of New- York, I separated a few species found in the impure drab- 

 colored limestone from Wayne county, New- York. 



The limestone containing these fossils became exposed only in the bed 

 of the canal during its excavation; and the low country, or deeply drift- 

 covered surface in the vicinity did not admit of any exposure of the rock 

 in place. The materials were thrown out of the excavation in connexion 

 with the soft marls of the Onondaga-salt group, and the specimens of rock 

 containing the fossils preserved the peculiar celluliferous structure and 

 characteristic color of the argillaceous limestone of that formation. Dif- 

 fering so especially from any known beds in the Niagara group, I did not 

 hesitate to refer them to the Onondaga-salt group, since there was no evi- 

 dence of any other formation in the neighborhood. 



Throughout the State of New- York, the country along the junction of 

 the Niagara and Onondaga-salt formations is low and level, or covered by 

 drift accumulations; and no opportunity ofi'ered of discovering any expo- 

 sure of similar beds along the course of the outcrop. In some places 

 in Monroe county, we have been able to trace the two formations to within 

 a few feet of their contact with each other ; but no fossiliferous beds, simi- 

 lar to those of Wayne county, have been found. At a later period,! my 



*The same reference of species had in fact been made during the Geological Sur- 

 vey; and they were thus published in the Report on the Fourth Geological District 

 in 1843. 



t After a considerable part of Vol. ii had been printed. 



[December, 1864.] 39 



