245 lyiGNiTic Stage 53 



Ledaparva, Pl. g, fig. 14. 



Syn. Nuaila parva Rogers, Trans. Amer. Philos. Soc,, vol. v, p. 340, 



1838. 

 Leda n. sp. Aid., Bull, i, Geol. Surv. Ala., p. 53, 1S86. 

 Leda robusta Aid., Bull. Amer. Paleont., vol. i, p. 69, pl. 6, figs. 



I, la. 



Rogers' original description. — "Shell ovate, inflated, rounded 

 before, not much produced, but rapidly tapering to a truncated 

 point behind, furnished with about twelve rather coarse concen- 

 tric folds or ridges, and a longitudinal gently depressed groove or 

 undulation of surface, running from near th^ beak to near the 

 posterior basal margin ; beaks nearly central ; anterior series of 

 teeth slightly arched ; posterior series nearly straight ; margin 

 entire ; cavity rather deep. lycngth, three-twentieths ; height, 

 two-twentieths of an inch." Coggin's Pt., Pr. Geo. Co., Va. 



This species shows great variation as regards size and surface 

 ornamentation. The specimen figured by Aldrich {loc. cit.) rep- 

 resents a marked variety showing very few concentric plications. 

 At Gregg's landing a somewhat larger form occurs, showing not 

 the broad concentric folds of Aldrich's figure, but a great many 

 rounded, concentric lines. This in turn is preceded by the form 

 styled b)^ us last yeox, Leda quercollis (Bull. Amer. Paleont., vol. 

 I, p. 169.) 



Specimens from Evergreen, Va., show charac?ters precisely like 

 the smaller, less robust specimens from Woods bluff. 



Localities ( Gulf States). — Alabama : Woods Bluff ; 1% miles ^ 

 w. s. w. of Choctaw Corner ; Gregg's Landing ; 

 4 miles above Hamilton Bluff, Alabama River. 



Type. — 



Specimen figured. — Woods Bluff ; Paleont. Museum, Cornell 

 University. 



Yoldia aldrichiana, Pl. 8, fig. 15. 



Syn. Leda elongatoidea ? Har. (non Aid.,) Bull. Amer. Paleont., vol. i, 

 pl. 14, fig. 10. 



Aldrich's elongatoidea having proven quite a different shell, we 

 venture to describe this species as new. 



Specific charaBerization. — Size and general form as indicated 

 by the figure ; anterior sub-basal margin tending to become rec- 

 tilinear ; shell rather thin and Voldia-like, transversed exteriorly 



