ie GEOLOGICAL SURVEY OF THE TERRITORIES. 
its valves near so abruptly truncated, but rounding and sloping forward 
gradually into the dorsal outline abov®. Possibly, I should call it Afod- 
tola pealet. 
“ Locality and position.—Missouri River, below Gallatin City, Mont. 
Cretaceous.” 
Genus TAPES Miuhlfeldt. 
TAPES HILGARDI Shumard. 
Plates 16, figs. 3 a, b, and ¢. 
Tapes hilgardi Shumard, 1860, Trans. St. Louis Acad. Sci., Vol I, p. 601. 
The following is Dr. Shumard’s description of this species (loc. cit.). 
‘‘ Shell ovate, transversely elongate, valves compressed, convex; ex- 
tremities rounded, the anal end narrower than the buccal, and in adult 
Specimens approaching to subtruncate; cardinal border long, curving 
gently from the beaks posteriorly; basal margin very gently convex; 
beaks situated about one-third the length of the shell from the anterior 
margin, rather short, nearly in contact; ligament area depressed, narrow- 
lanceolate ; pallial sinus lingueeform, extending above the middle of the 
height of the shell. The surface markings are not well preserved in any 
of the specimens before me. They show merely fine concentric lines of 
growth near uae basal margin. 
“Length, 2 inches; width, 1.27; thickness, 0.66. 
Locality y. ” Blais of Red River, Lamar and Fannin counties (Texas), 
occurring in septaria of the marly clay, near the base of the Lower Cre- 
taceous.” 
In the collections of the National Museum are some examples which I 
reier to this species, one of which is represented by fig. 3 6 and another 
by fig. 3 c, plate 16. These examples were sent by Mr. D. H. Walker, from 
Bell County, Texas, with other Cretaceous species. Fig. 3 a of the same 
plate is from a photograph of Dr. Shumard’s original drawing which he 
had gven to the late Mr. Meek before his death. This species perhaps 
belongs to the genus Baroda Stoliczska, but as nothing is yet known of its 
hinge ¢ or interior markings I prefer to leave it where ‘Shumard placed it. 
Genus PACHYMYA Sowerby. 
PACHYMYA? COMPACTA White. 
Plate 17, figs. 4a and 6. 
Pachymya? compacta White, Jan., 1880, Proc. U. 8. National Museum, vol. ii, p. 297. 
Shell small, narrower posteriorly than anteriorly, slightly gaping be- 
hind; beaks depressed, approximate, incurved, directed forward, their 
position being very near the front; basal margin broadly convex; pos- 
terior margin narrowly rounded ; postero-dorsal margin forming an 
oblique downward and backward "truncation of that part of the shell; 
cardinal margin nearly straight, subparallel with the basal margin, 
much shorter than the full len ‘eth of the shell; ligament short, its area 
depressed and sharply defined; front very short, depressed beneath the 
beaks and narrowly rounded below ; umbonal ridges prominent, angu- 
lar or subangular; the space above and behind them moderately broad 
and flattened ; the remainder of the valve somewhat regularly convex. 
Hinge and interior markings unknown. Surface marked by the ordi- 
nary concentric lines of growth. 
