MARYLAND GEOLOGICAL SURVEY 187 



Occurrence. — Talbot Formation. Wailcr, Bluff near Cornfield Har- 

 bor, St. Mary's County; Federalsburg, Caroline County. 



Collections. — Maryland Geological Survey, Johns Hopkins University, 

 and U. S. National Museum. 



Odostomia (Chrysallida) impressa (Say). 



Plate L, Figs. 5, 6. 



Turritella impressa Say, 1822, Jour. Acad. Nat. Sci. Phila., vol. ii, 1st ser., 



p. 244. 

 Chemnitzia impressa Stimpson, 1851, Shells of New England, p. 42. 

 Odostomia impressa Gould, 1870, Inv. Mass., Ed. Binney, p. 330, fig. 600. 

 Odontostomia impressa Dall, 1892, Trans. Wagner Free Inst. Sci., vol. iii, 



pt. ii, p. 251. 



Description. — "Shell dusky, acute at the apex; volutions six, with 

 about four acute, impressed revolving lines; labrum not thickened, a 

 slight indentation at its base, and a projecting angle within on its middle." 

 Say, 1822. 



This species is very common at Federals burg, but has not been ob- 

 served at any other locality. The characteristic revolving lines are clearly 

 shown on all the specimens. 



Length, 3.5 mm.; width, 1.25 mm. 



Occurrence. — Talbot Formation. Federalsburg, Caroline County. 



Collections. — Maryland Geological Survey, Johns Hopkins University. 



Odostomia acutidens Dall. 

 Plate L, Figs. 7, 8. 



Odostomia acutidens Dall, 1883, Proc. U. S. Nat. Mus., vol. vi, p. 331. 

 Odostomia conoidea Dall, 1892, Trans. Wagner Free Inst. Sci., vol. iii, pt. ii, 

 pp. 250, 251. 



Description. — " Shell solid, rude, yellowish- white, acute, six-whorled, 

 marked with lines of growth merely; suture evident, but not channeled; 

 whorls rather flat, except the last, which has a neatly rounded base ; aper- 

 ture with the outer lip acute, rounded to the columella, which stands out 

 from the surface of the shell, with a groove behind it, but no umbilicus ; 



