Logan.] The Invertebrates, Fort Pierre Group. 509 



indistinct, irregular, very fine, parallel striae between on the 

 body whorl ; aperture and lip unknown. 



"Length, about fifty-four hundredths inch; breadth of body 

 whorl, twenty-six hundredths inch ; apical angle, slightly conr 

 vex; divergence, thirty-seven degrees." 



In Meek's type specimen the lip and apex are wanting ; in 

 those collected by the writer the spire is entire but the lip is 

 wanting. The spire is much as he restored it, but consists of 

 two more whorls than is represented in his specimen. I col- 

 lected a few imperfect specimens of this species a few miles 

 west of Jackson's ranch, in Cherry Creek caiion, in Cheyenne 

 county. They were found associated with Lucina occidentalis , 

 and probably occur near the upper limit of the Fort Pierre. 



JBaculites ovatus Say. Plate cix, fig. 3. 



Baculiies ovatus Say, 1821, Silliman's Am. Journ. Sci., Phil., vi, 196, pi. v, 

 ff. 5, 6; and 1830, Am. Journ. Sci. and Arts, xviii, 248, pi. i, ff. 6, 7, 8; also 

 1834, Syn. Org. Rem. Cret. Group U. S., 42, pi. v, ff. 5, 6, Hall and Meek, 

 1854, Mem. Am. Acad. Arts and Sci., v (n. s.), 399, pi. v, ff. la, b, pi. vi, ff. 

 1-7; Meek, 1876, Geol. Surv. Terr., pi. xx, ff. la, b, and 2a, b, d. 



Baculites baculus M. & H., 1861, Proc. Acad. Nat. Sci. Phil., xxn, 442. 



Meek's description : " Shell attaining a large size, elongated, 

 and rather gradually tapering ; section ovate, the antisiphonal 

 side being more broadly rounded than the opposite ; aperture 

 of the same form as the transverse section ; extension of the lip 

 on the siphonal side long, tapering, and narrowly rounded at the 

 end ; lateral sinuses of the same depth and about half to one- 

 third the greater diameter of the shell ; antisiphonal margin 

 of the lip prominently rounded in outline ; surface of young 

 and medium-sized specimen generally nearly smooth, while the 

 non-septate part of the adult shell is provided with broad, un- 

 defined, obliquely transverse ridges or undulations that are 

 parallel to the obscure lines of growth, and become nearly or 

 quite obsolete as they approach the siphonal side, on which 

 they are rarely represented by very small irregular ridges, 

 scarcely distinct from the marks of growth. 



"Septa moderately closely arranged, or sometimes a little 

 crowded ; siphonal lobe nearly twice as wide as long, and pro- 

 vided with two large terminals widely separating more or less 



