446 Systematic Paleontology 



Type Locality. — Tippah County, Mississippi. 



Pyropsis perlata Conrad is best characterized by a spire 'depressed 

 almost to flatness, an angulated and abruptly constricted body whorl, an 

 external surface ornamented with rugose, unequal spirals. The synonymy 

 of the species is in a well-nigh hopeless state. Of the three names most 

 intimately concerned, the first, Pyropsis richardsoni (Tuomey), is 

 founded on an unfigured type which bas been lost and which was originally 

 described in less than two lines ; the second, Pyropsis perlata Conrad, was 

 founded on a shell, perfectly preserved excepting for the very tip of the 

 spire and the anterior extremity of the canal ; the third, Pyropsis elevata, 

 was founded on an inside cast which has retained none of the original 

 ornamentation. This has been omitted from the above synonomy because 

 of an apparently less depressed spire and a less abruptly constricted body 

 whorl. It is quite probable that P. richardsoni and P. perlata are spe- 

 cifically identical, but it is impossible to prove it, and for that reason it 

 does not seem wise to perpetuate a name which can never be adequately 

 defined unless the lost type should come to light. 



The Matawan casts referred to this species are much smaller than the 

 shells preserved in the Monmouth. 



Occurrence. — Matawan Formation. Camp U & I, opposite Post 192, 

 Chesapeake and Delaware Canal, Delaware. Monmouth Formation. 

 Bohemia Bridge, Cecil County ; Brightseat, and Brooks estate near Seat 

 Pleasant, Prince George's County, Maryland. 



Collections. — Maryland Geological Survey, Philadelphia Academy of 

 Natural Sciences. 



Outside Distribution. — Bipley Formation. Exogyra costata zone, 

 Tippah County, Mississippi. 



Pyropsis trochiformis (Tuomey) Gabb 

 Plate XVI, Figs. 1, 2 



Pyrula trochiformis Tuomey, 1854, Proc. Acad. Nat. Sci., Phila., vol. vii, p. 



169. 

 Tuclicla trochiformis Meek, 1864, Check List Inv. Fossils, N. A., Cret and 



Jur., p. 22. 

 ? Pyropsis trochiformis Gabb, 1876, Proc. Acad. Nat. Sci., Phila., pp. 284, 285. 



