MARYLAND GEOLOGICAL SURVEY 209 



coming very pronounced. It is a very old form, appearing in the Oligo- 

 cene of Florida. It has been found in the Miocene of Maryland, Vir- 

 ginia, and the Carolinas, in the Pliocene of the Carolinas and Florida, 

 and in the Pleistocene of Maryland and South Carolina. In the Eecent 

 it occurs on the southeast coast of the United States, in the Antilles and 

 on the coast of California. 



Width, 7 mm. ; height, 4 mm. 



Occurrence. — Talbot Formation. Wailes Bluff near Cornfield Har- 

 bor, St. Mary's County. 



Collections. — Maryland Geological Survey, Johns Hopkins University, 

 and U. S. National Museum. 



Genus YOLDIA Moller. 

 YOLDIA LIMATULA (Say). 



Plate LXV, Figs. 9-12. 



Nucula limatula Say, 1831, Amer. Conch., pi. xii. 

 Leda limatula Holmes, 1858, Post-PL Fos. S. C, p. 18, pi. iii, fig. 8. 

 Leda (Yoldia) limatula Dall, 1889, Bull. U. S. Nat. Mus., No. 37, p. 44, pi. 

 xlix, fig. 5; pi. lvi, fig. 1. 



Description. — " Oblong-ovate, rostrated, pellucid; beaks subcentral, 

 not elevated; margin entire Shell transversely elongated sub- 

 ovate, green olive, nearly pellucid, smooth, polished, with slight induc- 

 tions [sic] of increment; beaks not prominent above the curve of the 

 hinge margin; hinge margin anteriorly abruptly compressed; the com- 

 pression not reaching the tip; rectilinear nearly to the tip which is a 

 little recurved; posteriorly almost regularly, but obtusely arquated; pos- 

 terior margin regularly rounded : anterior margin somewhat rostrated, 

 not truncated : within a little perloceous : margin entire : line of the teeth 

 slightly interrupted and a little angulated at the fossit, extending more 

 than two-thirds of the length of the shell, rectilinear before and behind : 

 teeth prominent, numerous, acute, much angulated at their bases and 

 longer than the breadth of their bases: fossit triangular, short, rather 

 small, and but little oblique." Say, 1831. 

 15 



