200 CKETACEOUS PERIOD. 



Numerous examples of B. ovatus were also obtained from Gallinas 

 Creek, New Mexico, some of wliicli were quite large. A large proportion 

 of these were typical forms of the species. A transverse section of one of 

 these is shown in figm-e 4 a, Plate XIX. Many of the examples, associated 

 with these typical ones, were, however, quite constant in having theu' sides 

 more flattened than those of typical form, gi^^ng an outline of transverse 

 section, such as is shown in figure 5 h. The septa in all these last-named 

 examples coiTespond so nearly with those of the typical forms of B. ovatus 

 as described and figured by Hall and Meek that I am disposed to regard 

 them as only a variety of that species. The plan of the septa in this variety 

 is shown in figure 5 a, and still more clearly in figure 5 c. 



Family SCAPHITIDiE. 



Genus SCAPHITES Parkinson, 1811. 



Scaphites Warreni Meek and Hayden. 

 Plate XIX, fig. 3 a. 

 Scaphites Warreni Meek and Hayden, 1860, Proc. Acad. Nat. Sci. Pbila., 177. 



The collections contain a single specimen of this species from Creta- 

 ceous strata tlu-ee miles southwest of San Mateo, New Mexico, which, 

 although too imperfect for detailed description, is satisfactorily identified by 

 its visible external characters. 



The type-specimens of Meek and Hayden were obtained near the 

 Black Hills, in Nebraska ; the following being the substance of theii- descrip- 

 tion: — 



" Shell small, transversely subovate, moderately compressed, rounded 

 on the dorsum ; volutions subcylindrical, increasing gradually in size ; 

 non-septate poition of the last turn slightly compressed laterally and deflected 

 from the regular cui-ve of the others so as to become nearly or quite discon- 

 nected at the apeitiu-e. 



" Surface of the inner whorls ornamented by numerous small costse, 

 which increase chiefly by implantation, and all cross the dorsum very reg- 

 ularly without arching ; on the sides of the uonseptate outer chamber, 



