946 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 127 
Horizon and locality.—Carters formation (O-xoplecia bed) in Alabama: In 
the quarry 0.3 mile north of Gate City, Leeds (15’) Quadrangle. 
Discussion—This species is characterized by having a fairly large size and 
somewhat nasute front. It differs from S. basilica in having costellae of fairly 
even size and a more nasute front. It is unlike S. medialis in ornamentation and 
outline. It is also unlike S. grandimusculosa in being elongate rather than trans- 
verse and in having a less square and thickened muscle area in the pedicle valve. 
It has the form of S. auburnensis nasuta but is differently ornamented and has 
a smaller muscle area in the pedicle valve. It suggests S. dignata Fenton, but 
that species is larger, has a larger pedicle muscle scar and more differentiated 
ornamentation. 
STROPHOMENA ROTUNDA Wilson 
Strophomena rotunda Witson, Trans. Roy. Soc. Canada, ser. 3, vol. 39, sec. 4, p. 137, pl. I, 
fig. 8, 1945; Geol. Surv. Canada, Bull. 8, p. 106, pl. 9, fig. 8, 1946. 
Type.—Holotype: G.S.C. 7589. 
Horizon and locality.—Leray =Chaumont— Rockland beds in Ontario, Can- 
ada: On road east from Skead, east of Ottawa. 
STROPHOMENA ? SCULPTURATA Bassler 
Plate 222, C, figure 4 
Strophomena sculpturata BASSLER, Cambrian and Ordovician: Geol. Surv. Maryland, p. 250, 
pl. 40, fig. 1, 1919. 
This is one of a number of species that have been described in North America 
and abroad which are characterized by the stropomenoid form but, in addition 
to the normal costellae, are more or less strongly wrinkled. The wrinkling is 
not like that of Leptaena but is more suggestive of Bellimurina. Little is known 
of the interior details of these species. The type of wrinkling displayed appears 
in many stocks that are demonstrably different, and this makes the wrinkling in 
itself a dubious character for generic differentiation. The same type of orna- 
mentation also occurs in a rafinesquinoid stock. 
Types.—Holotype : 66165 ; paratypes: 66165a-c. 
Horizon and locality—Martinsburg formation (Simuites zone) in Pennsyl- 
vania: I mile south of St. Thomas, Mercersburg (15’) Quadrangle. 
STROPHOMENA SEPTATA Winchell and Schuchert 
Strophomena septata WINCHELL and SCHUCHERT, Amer. Geol., vol. 9, p. 285, 1892; Geol. 
Minnesota, vol. 3, pt. 1, p. 390, pl. 30, figs. 1-3, 1895. 
Horizon and locality—Decorah formation (Ion member) in Minnesota. 
STROPHOMENA VENUSTULA Wilson 
Strophomena venustula Witson, Trans. Roy. Soc. Canada, ser. 3, vol. 39, sec. 4, p. 138, pl. 1, 
figs. 6, 7, 1945; Geol. Surv. Canada, Bull. 8, p. 107, pl. 9, figs. 6, 7, 1946. 
Types.—Holotype: G.S.C. 7591; paratype: G.S.C. 7599. 
Horizon and locality—Leray =Chaumont— Rockland beds in Quebec, Can- 
