OKETACEOUS TEKIOD. 185 



Family GLOSSIDiE. 



GENUS VENIELLA Stoliczska, 1870. 

 Veniella goniophora Meek. 

 Veniella goniophora Meek, 1875, Paleont. Upper Missouri River, 152. 



Some imperfect examples of this species were obtained from Cretaceous 

 strata southeast of Paria, Utah. Mr. Meek's types of the species were 

 obtained from the valley of the Missom-i Eiver, near Fort Benton. The 

 above-named work, which is now issuing from the press, contains full 

 descriptions and illustrations, for which the examples in hand are too imper- 

 fect to furnish a satisfactory basis. 



Family MACTRIDJ3. 



Genus MACTEA Liunajus. 



Mactra? incompta White. 

 Plate XVII, fig. 6 a and &. 



Shell small, transversely subovate in marginal outline ; valves moder- 

 ately convex ; beaks somewhat prominent, placed a little more than one- 

 third the length of the shell from the front ; dorsal border strongly arching ; 

 base bi'oadly rounded; front regularly but strongly rounded; posterior 

 border broadly rounded down to the basal margin, which it meets at an 

 obtuse angle, and which is thei'e met by an obscure, broadly-curving umbo- 

 nal ridge. Surface marked by somewhat regular, small but distinct, raised, 

 concentric striae. The general aspect of the shell, the absence of an exter- 

 nal ligament, and the presence of a well-developed lateral tooth in the left 

 valve (all of the hinge yet seen) suggest its reference to the genus Mactra, 

 but it may probably be found to differ from the typical forms of that geiuis 

 by the discovery of the whole hinge. 



Length, eighteen millimeters ; height, from beaks to base, fourteen mil- 

 limeters ; thickness, nine millimeters. 



Position and locality. — Strata of the Cretaceous j)eriod ; five miles above 

 Pueblo, Colorado. 



