64 EEPOET OF THE 



other fossiliferous strata— belong to this group; while- more 

 than another fifth belong to the Hamilton Group. But little has 

 yet been done toward the identification of the numerous species, 

 in consequence of the long expected, but long delayed, appear- 

 ance of Prof. Hall's third volume on the Palaeontology of New 

 York. The highest members of the formation in Monroe county, 

 contain numerous ichthyodorulites and other traces of fishes, 

 the most perfect of which have been furnished by Judge Chris- 

 tiancy, from his quarry near Dundee. A finely preserved spine 

 from this locality, exhibits the generic characters of New- 

 berry's Machceracanthus* except that it is solid throughout. I 

 have also a traditional account of a pair of powerfully armed 

 fish jaws. The same quarry contains an abundance of beauti- 

 fully preserved Tentaculites, showing the telescopic structure of 

 the shell; a large encrinital stem, and. a Oomphoceras (n. sp.), 

 which is found again in the highest beds of the formation at 

 Crawford's quarry, beyond Prcsque Isle. A little lower down, 

 in the borders of the oolitic beds, we find a lihynchanella (n. 

 sp.). At Stony Pt. and Pt. aux Peaux, the formation is much 

 shattered, and embraces large concretionary masses several 

 feet in diameter, which easily separate in concentric layers. 

 A similar structure was afterwards seen at Thunder Bay 

 Island, forming domes twelve and a-half feet in diameter, 

 rising up through the rocky floor of the island. Here, 

 however, a distinct coralline structure was discovered, 

 which has led to the conviction that the structure at Stony 

 Point, is also organic. Numerous trilobites occur in the rocks 

 at Monguagon, in Wayne county, among which Phacops bvfo 

 is conspicuous. 'I wo or three species of Euomphalus wore seen 

 at Middle Island, and a very large Euomphaloid shell six or eight 

 inches across, has been obtained from the west end of Lake 

 Erie. From Mackinac, besides Phacops bufo, Proetus (sp?) and 

 the other forms noticed by Prof. Hal!,"j" I have detected onlj T a 

 Cyathophy'lloid coral. From Little Traverse Buy, I have Spirit 



* " Fossil Fishes from the Devonian Rocks of CLio," in Bulletin of the National Institute, 

 Jan. 26, 1867. 

 ■fFosur & Whi.ney'sEeport, Vol. H, p. 166. 



