MARYLAXD GEOLOGICAL SURVEY 231 



Family Cy^CID/E. 



Genus C/ECUM Fleming. 

 C^CUM CALVEETENSE n. Sp. 



Plate LV, Fig. 10. 



Description. — This species is marked by very fine, closely-set, irregular 

 annulations, and no other sculpture. 



Length of segment, 4 mm.; diameter (maximum), 0.8 mm. 



Occurrence. — Calvert Formation. Church Hill, 3 miles west of 

 Centerville. 



Collection. — Maryland Geological Survey. 



C-fflCUM patuxentium n. sp. 

 Plate LV, Figs. 11, 12. 



Description. — The only sculpture consists of from 30 to 40 strong, reg- 

 ular, closely-set annulations. 



This species bears a strong superficial resemblance to C. floridanum 

 Stimpson, but differs from it in possessing no longitudinal markings. 



Length of segment, 2.2 mm. ; diameter, 0.5 mm. 



Occurrence. — Choptank Formation. Greensboro, Dover Bridge, Cor- 

 dova, Peach Blossom Creek, Jones Wharf, Governor Eun (lower bed). 



Collection. — Maryland Geological Survey. 



C^cuM greensboroense n. sp. 

 Plate LV, Fig. 13. 



Description. — Shell apparently smooth and highly polished, but under 

 high magnification showing irregular, almost obsolete annulations which 

 are strongest at the ends of the segments. 



Length of segment, 3 mm. ; diameter, 0.5 mm. 



Occurrence. — Choptank Formation. Greensboro. 



Collection. — Maryland Geological Survey. 



