Maryland Geological Survey 487 



TURRITELLA BONASPES n. Sp. 



. Plate XVII, Fig. 10 



Turritella (?) sp. Weller, 1907, Geol. Survey of New Jersey, Pal., vol. iv, pi. 

 lxxix, figs. 8, 9. 



Description. — Shell rather small for the genus, and quite slender; 

 whorls probably about ten in number, the early volutions quite feebly, 

 the latter evenly concave, and slightly overhanging the suture; apical 

 angle not exceeding 12°; axial sculpture not developed; spiral sculpture 

 on the later turns of fine, flattened, primary lirae, with intercalated, linear 

 secondaries, and between the posterior primary and the suture, two spirals 

 midway in prominence between the primaries and the secondaries ; suture 

 lines deeply impressed, the posterior margin almost horizontal, the ante- 

 rior slope about 45° ; characters of base unknown. 



Dimensions. — Altitudes 20 mm., maximum diameter 5 mm. 



This species strongly suggests T. jerseyensis Weller of the Magothy of 

 New Jersey, and may quite possibly prove to be identical with that species. 

 However, Weller makes no mention of the development of any intercalated 

 secondaries nor of the two lirte between the posterior spiral and the suture. 

 The secondaries are exceedingly fine and may have been obliterated in the 

 New Jersey form. Perhaps the most striking similarity in the two shells 

 is in the relatively loose coiling and consequent deepening of the sutural 

 channel in the later whorls. It is very abundant at the type locality but 

 has not been recognized elsewhere. 



Occurrence. — Magothy Formation. Good Hope Hill, District of 

 Columbia. 



Collection. — Maryland Geological Survey. 



Turritella delmar n. sp. 

 Plate XVII, Figs. 3, 4 



Description. — Shell small for the genus; elongate-conic, not conspicu- 

 ously slender ; whorls flattened, probably not more than ten in number, 

 converging at an angle of 12° ; spiral sculpture very fine and crowded, the 

 liras subequal, twelve to fifteen in number on the later turns; fortuitous 



