418 
PROCEEDINGS OF THE ACADEMY OF 
prominent, acute, incurved and turned backward; cardinal lines nearly 
straight, beyond the dental series curving rapidly to the extremities, of which 
the anterior is broadly rounded; ventral side with a slight general convexity, 
varied by a broad shallow sinuation in front of the middle, which extends 
one-third the distance up to the beaks. Pallial line entire; posterior adductor 
forming a round deep scar. Cardinal angle between the beaks varying from 
115° to 125° ; teeth numerous, in a series not perceptibly interrupted between 
the beaks, those on the anterior slope posteriorly angulated, those on the pos¬ 
terior slope rather larger; the remoter often transverse to the hinge plate ; 
those nearer the beak angulated forwards ; between the beaks the hinge plate 
is somewhat widened, and the teeth are slender, long and crowded in a scarcely 
interrupted series. Shell massive, thickened around the smooth ventral mar¬ 
gin ; external surface marked by numerous unequal lines of growth ; casts 
nearly smooth. 
Length of an average specimen 1-45 (100) ; height *80 (55) ; convesrity of 
one valve *26 (18) ; length of posterior end *59 (41) ; anterior end *96 (66) ; 
height of beaks above line connecting extremities *46 (32) ; number of teeth 
in posterior series from 12 to 16 ; in anterior from 30 to 40. 
Localities. —Marshall, Battle Creek, Moscow, and at nearly every other ex¬ 
posure of the Marshall Sandstone in the southern part of the State. The 
most abundant fossil in the group, generally occurring in beds ten or twelve 
inches in thickness. 
This species has about the proportions of Cucullella tenuiarata , Sandb. 
(Verstein, 276, Taf. xxix. 4), but specimens of the latter from Kirschweiler, 
in the cabinet of Dr. Rominger, are more symmetrically furrowed, and pos¬ 
sess fewer teeth. 
This is, perhaps, the species described by Dr. Stevens as Leda nuculceformis 
(Sill. Jour. [2], xxv. 262), but it is not Leda , and the number of teeth is 
much too great for his description. 
Named in honor of Bela Hubbard, Esq., of Detroit, who published in 1840 
the first notice on record of the interesting sandstones under consideration, 
and designated the generic relations of several of the more abundant fossils. 
Var. prolata. A form which I am inclined to regard as only a variety of the 
preceding, is very ventricose, and more elongated anteriorly, with a greater 
number of teeth. 
Length 1-46 (100); height *69 (47); convexity of one valve *28 (19); length 
of posterior end *38 (26); of anterior end 1*06 (72). 
Localities. —Moscow and Battle Creek. 
Nucula Iowensis. White and Whitfield (Proc. Bos. Soc. Nat. Hist., Feb. 
1862, p. 298).—Shell small, triangularly ovate, ventricose, with prominent 
incurved, subterminal beaks. Cardinal plate forming an angle of 95°, but the 
dorsal outline of the shell, from the prominence of the beaks, forms an angle 
of 80°. Anterior and posterior slopes truncated ; anterior extremity rounded, 
ventral border semi-elliptic. Long end with about 11 teeth ; short end with 
6 very inconspicuous ones. Pallial impression entire, connecting the deep 
adductor scars; anterior scar nearly terminal, lenticular, with a small oval 
scar above ; posterior scar oval, scarcely above the extremity. Shell thickened 
near the margin. 
Length *47 (100); height *40 (85) ; convexity -26 (55) ; distance from beak 
to line joining extremities *27 (57). 
Localities. —Battle Creek and Sec. 7, Wyoming, Kent county. 
These specimens possess a somewhat greater number of teeth than the Iowa 
ones, according to the author’s description. In general form they recall 
Cucullcea antiqua, Sow., from the old red sandstone of Felindre (Murch. Sil. 
Syst., pi. iii. fig. 120). 
Nucula sectoralis, n. sp.—Shell rather small, ventricose, sectoriform, with 
nearly central beaks. Anterior cardinal slope straight; posterior, nearly so, 
