626 THE PALEONTOLOGY OF MINNESOTA. 
{Saffordia ventralis. 
Named asa small compliment to the veteran geologist, Prof. J. M. Safford, State 
Geologist of Tennessee. Science is indebted to him for several most valuable works 
on the geology of his state, while personally I am under great obligations to him 
for assistance in the way of specimens and advice. 
SAFFORDIA VENTRALIS, 7. Sp. 
PLATE XLI, FIGS. 3441. 
Shell transversely subovate, the hight and length very nearly as four is to five; 
beaks small, declining, situated at the anterior extremity of the distinctly arcuate 
dorsum, and projecting forward as far as the margin of the shell beneath it. Anterior 
margin distinctly concave in the middle, the lower part narrowly rounded; ventral 
margin rather strongly convex, posterior margin subtruncate, a little oblique, the 
upper half straight or slightly sinuate, the lower rounded. Surface of valves mod- 
erately convex, with a very inconspicuous umbonal ridge between which and the 
dorsal edge there is a shallow sulcus. Escutcheon well defined, extending the full 
length of the hinge, in a dorsal view very narrow between the beaks, wide at the 
middle, and narrowing again posteriorly. Lunule sharply defined, very deep, nearly 
twice as long as wide. Surface marked by subimbricating concentric growth lines. 
These are rather small but sharp and of nearly equal size for a short distance 
beneath the cardinal edge, and only a few of them seem to cross the umbonal ridge. 
Internal characters of hinge as shown in figures 37 and 41. Anterior muscular scar 
of medium size, subcircular, deep, showing very prominently on casts of the interior; 
pallial line and posterior muscular impression very faint. 
This species is distinguished from S. sulcodorsata by its shorter form, focninal 
beaks, and more rounded ventral margin. 
Formation and locality.—Upper beds of the Hudson River group near Spring Valley, Minnesota, and 
Iron Ridge, Wisconsin. 
SAFFORDIA suLcopORSATA Ulrich. 
PLATE XLI, FIGS. 32 and 33. 
Cuneamya sulcodorsata ULRICH, 1892. Nineteenth Ann. Rep.Geol. and Nat. Hist. Sur. Minn., p. 248. 
Shell small, moderately convex, oblong-subquadrate, with the dorsal and ventral 
margins subparallel and gently convex, the posterior end truncate, very slightly 
produced and sharply rounded at the base, anterior end very short (long for the 
genus), narrowly rounded. Beaks subterminal, declining forward, strongly incurved, 
projecting forward rather than upward; umbonal ridge moderately prominent, not 
angular. Dorsal slope with a distinct expanding sulcus; ventral and anterior slopes 
gently and uniformly convex. Hinge line, posterior to the beaks, long, the edge 
