WHiTEAvES.] FOSSILS OF HAMILTON FORMATION OF 0>fTARIO. 117 



istic cast and a smaller one, both of which show, more or less dis- 

 tinctly, either the blunt angulation of the periphery of the body whorl 

 or the distant nodes on the shoulder above it. 



The reference of this shell totheLinnaean genus Turto does not seem 

 to the writer to be entirely satisfactory, and it is not easy to define in 

 what particular it differs from Platyostoma. 



PlATTOERAS CARINATU3I, Hall. 



Platyceras carinatum, Hall. 1862. Fifteenth Rep. N. York St. Cab. Nat. Hist., 



p. 33. 

 " " " 1876. Illustr. Dev. Foss., pi. 2, figs. 12-29 and (1879) 



Pal. State N. York, vol. V., pt. 2, p. 5, pi. 2, figs. 

 12-29. 



Township of Bosanquet, Mr. J. Pettit, 1885: five specimens. 



Platyceras qtiinquesinuatum, Ulrich. 



Plate 1.5, figs. 5 and G, and plate 16, tiy:. 5. 



Platyceras quinquesinuatum, Ulrich. 1886. Contr. to Americ. Palseont., Cincinnati, 



vol. I., p. 29, pi. 3, figs. 4, 4a, and 4b. 



Xear Thedford, Eev. J. M. Goodwillie, 1882 : three fine specimens. 



This species, which is very nearly related to some forms of the P. 

 symmetricum of Hall from the Hamilton Formation of the State of 

 New York, was described from specimens collected from the " Middle 

 Devonian " of the Falls of the Ohio. 



Platyceras (Orthonychia) conicum, Hall. 



Plate 16, fig. 4. 



Platyceras conicum, Hall. 1862. Fifteenth Eep. N. York St. Cab. Nat. Hist., p. 31. 

 Platyceras (Orthonychia) conicum, Hall. 1876. Illustr. Dev. Foss., pi. 1, figs. 13- 



23, and pi. 2, figs. 30 and 31. Also, Pal. State N. 



York, vol. v., pt. 2, (1879) p. 3, pi. 1, figs. 13-23, 



andpl. 2, figs. 30and31. 



One fine specimen of this species was collected in the township of 

 Bosanquet by Mr. J. Pettit in 1868, another near Thedford in the same 

 township by the Eev. Hector Cun-ie, and a third, also near Thedford, 

 by the Eev. J. M. Goodwillie, in 1882, all of which are now in the 

 Museum of the Survey. The species was first recorded as occurring 

 near Widder by Professor Hall in 187G. 



