582 NEW SPECIES OF CRETACEOUS FOSSILS. 
CONCHIFERA. 
INOCERAMUS SAGENSIS. (N. 8.) 
(Tab. VIL, fig. 3.) 
Specific character.—Subovate or ovato-rhomboidal, convex, a wing-like extension of the anterior margin. 
Beaks blunt, slightly prominent. Angle formed by the hinge-line and axis a little less than a right 
angle. .Broad, concentric, festoon-like, oval wrinkles of the surface. Length four inches; width three 
inches. 
Relations and differences.—This fossil approaches in form to J. myteloides of Goldf., but it is wider 
transversely, has no distinct concentric striae between the broad wrinkles; beaks blunter; more elliptical 
in outline ; hinge-line longer. From J. Cripsii, which it also somewhat resembles, it differs in being 
much more gibbous, and in the direction and dimensions of the hinge. 
From the cretaceous formation on Sage Creek, southern tributary of the Cheyenne, associated with 
L. Barabini (?) and L Nebrascensis. 
INOCERAMUS NEBRACENSIS. (N. 8.) 
(Tab. VIIL., fig. 1.) 
Specific character.—Obliquely subovate or flatly rhomboidal egg-shaped; moderately convex. Umbos 
blunt and somewhat prominent. The hinge-line and axis form an acute angle of about 45°. Some twenty 
or twenty-one oblique, oval, concentric undulations of the surface, distinct but not prominent ; broad, but 
faint rays, diverging from the umbo to the circumference. 
Relations and differences.—This Inoceramus differs from J. planus, which it most nearly approaches, in 
being less circular, more convex, more inequilateral, umbos more prominent and gibbous, concentric 
undulations or folds more regular, angle formed by the hinge and axis more acute. 
From the eretaceous formation on Sage Creek, Nebraska. The nacre of the shell, as well as most of 
those found associated with it on Sage Creek, is in as good a state of preservation as that of dead shells 
now on the sea-shore. 
CUCULLAA NEBRASCENSIS. (N. 8.) 
(Tab. VIL., fig. 1, and 1, a.) 
Specific character.—When both valves are united, this shell is heart-shaped or cardiform. The indi- 
vidual valves are subrhomboidal, oblique, inequilateral, equivalve ; numerous minute, unequal, transverse, 
concentric strix ; hinge straight, and gently curved upward towards the beaks, which are slightly incurved, 
and not very distant; area with seven or eight rhombic furrows (formed by the margin of imbricated 
lamelle). Transverse, lateral teeth three, both at anterior and posterior side, with three accessory 
lamelle, the upper and under surface of which are roughened with fine transverse serrations. Central 
longitudinal teeth irregular. Anterior muscular impression long oval, and bounded beneath by a sharp, 
shelly projection, posterior rectangular 3 shell moderately thick. Length (with beak), two inches; 
breadth the same. 
Relations and differences.—In its general Shape this species is not unlike C. transversa, from the 
cocene tertiary, described and figured by William B. and H. D. Rogers, p. 373, Pl. XXIX., fig. 1, Con- 
tributions to the Geology of the Tertiary Formations of Virginia, Second Series 3 it differs, however, in 
several essential specific peculiarities ; in the form of the lateral teeth, and their number on ‘thi posterior 
side; in having no longitudinal striz, and the inner border not being crenulated ; and in having three 
more furrows on the area of each valve. 
From the cretaceous formation of the Fox Hills, between the Cheyenne and Moreau Rivers. 
