MARYLAND GEOLOGICAL SURVEY 351 



Astarte vicina Conrad, 1863, Proc. Acad. Nat. Sci. Phila., vol. xiv, p. .578. 

 Astarte exaltata Conrad, 1863, Proc. Acad. Nat. Sci. Pliila., vol. xiv, p. 578. 

 Astarte vicina Meek, 1864, Miocene Check List, Smitb. Misc. Coll. (183), p. 7. 

 Astarte exaltata Meek, 1864, Miocene Check List, Smith. Misc. Coll. (183), p. 7. 

 Astarte vicina Dall, 1903, Trans. Wagner Free Inst. Sci., vol. iii, pt. vi, p. 1489. 

 Astarte exaltata Dall, 1903, Trans. Wagner Free Inst. Sci., vol. iii, pt. vi, p. 1489. 



Descriftion. — " Trigonal, with a distant, somewhat regular, impressed 

 line; lunnle much excavated; apices acute. 



"Apices prominent: lunule dilated, deeply excavated, subcordate, 

 separated from the disk, particularly near the beaks, by a subacute 

 angle : beaks prominent, approximate, acute, curved backwards : liga- 

 ment margin concave : umbones convex." Say, 182-i. 



Margin posterior to the beak nearly straight, anterior to the beak 

 profoundly concave. The sulcations of the umbo gradually change into 

 obscure undulations over the rest of the surface. Margin crenulated or 

 smooth. The anterior, basal, and posterior margins form a nearly 

 symmetrical curve. Umbonal region thick; cardinal teeth strong. 



Length, 18 mm.; height, 18 mm.; diameter, 5 mm. 



Occurrence. — St. Mary's Formation'. St. Mary's River. Calvert 

 Formation. 3 miles south of Chesapeake Beach, Plum Point. 



Collections. — Maryland Geological Survey, Johns Hopkins University. 



Astarte thomasii Conrad. 

 Plate XCIV, Figs. 1, 2. 



Astarte Thomasii Conrad, 18.5.5, Proc. Acad. Nat. Sci. Phila., vol. vii, p. 367. 

 Astarte Thomasii Conrad, 1863, Proc. Acad. Nat. Sci. Phila., vol. xiv, p. 578. 

 Astarte Thomasii Meek, 1864, Miocene Check List, Smith. Misc. Coll. (183), p. 7. 

 Astarte Thomasii Conrad, 1866, Amer. Jour. Conch., vol. ii, p. 72, pi. iv, iig. 16. 

 Astarte Thomasii Whitfield, 1894, Mon. xxiv, U. S. Geol. Survey, p. 55, pi. viii, 



figs. 3-7. 

 Astarte Coheni Dall, 1903, Trans. Wagner Free lust. Sci., vol. iii, pt. vi, p. 1489 (in 



part). 



Description. — " Triangular, not ventricose, inequilateral; ribs concen- 

 tric, robust, recurved; concentric lines more or less marked, minute;, 

 toward the posterior end the ribs suddenly become obsolete; extremity 

 truncated, nearly direct, or sloping inwards; inner margin crenulated; 

 luniile large, ovate, acute, deeply excavated." Conrad, 1855. 



