376 CONTRIBUTIONS TO THE GEOLOGY OF 



to the base; margin slightly concave at the lunule, which is deep, 

 wide and ovate ; inferior margin delicately crenulated within. Length, 

 one inch four-tenths ; breadth, two inches two-tenths. " 



Locality, peninsula, between the Potomac and Rappahannock rivers, 

 in Virginia, in the eocene. 



Bemarks.— This species may readily be distinguished from the C. 

 melina, which it somewhat resembles, by its* less thickness, and by the 

 crenulation on its inner margin, but especially by its different outline 

 being much more contracted on its anterior side. 



Fasciolaria rhomboidea. Plate XXX., fig. 3. 



Specific character. — -Shell turrited, fusiform, and nearly smooth, 

 greatest dilatation about 4.he middle, spire conical, whorls convex, with 

 longitudinal, obsolete or interrupted striae, the lower seven or eight 

 upon the body whorl, and those upon the upper whorls, being distinct 

 and slightly undulated. On the body whorl are ten or eleven very 

 faint, brown, narrow, longitudinal lines, three of which are traceable 

 upon the spire. Transverse striae, distinct, moderately distant, and 

 arcuated. Aperture a little less than two-thirds the length of the 

 shell, columella arcuated, plicated with three very oblique folds, the 

 middle one the most elevated, labium delicately striated within the 

 edge, beak slightly recurved. Length, two inches four-tenths j breadth, 

 one inch two-tenths. 



Locality, Surrey county, Virginia, meiocene. 



Description. — This is a thin shell, though not difficult to procure en- 

 tire. From the F. mutabilis, the only other species of our tertiary, it 

 will readily be known by the greater length and arcuation of its beak, 

 by its less regularly fusiform outline, and by the difference in the num- 

 ber of its whorls, and of the plications on the columella. The high 

 preservation of the specimen from which the description has been 

 taken, permits us to trace upon its whorls its longitudinal coloured 

 bands, affording a very interesting specific character. 



