AitT. 14 FOSSIL. MOLLUSKS FROM THE MIOCENE MANSFIELD 9 



meridionalis ; the posterior extremity is less pinched and the nepionic 

 shell has coarser and shorter radially extending undulations. 



Type locdity. — U. S. G. S. station 1/244, right bank of James 

 River 1% miles below Claremont Wharf, Va., from lowest bed. 



O ccu)'i'enGe. — St. Marys formation, zone 2, type locality, and at 

 the following localities: U. S. G. S. station, 1/543, about 1 mile be- 

 low type localitj^, from lowest bed; U. S. G. S. station 1/241, right 

 bank of James River, Cobham Bay, bed outcropping at water level. 



CKASSATELLITES (CRASSATELLITES) MERmiGNALIS UKBANNAENSIS. new subspecies 



Plate 4, figures 3, 4 



Shell large, moderately thin, low, subovate and inequilateral, the 

 posterior side being longer and more attenuated. Outline of anterior 

 margin narrowly rounded, ventral margin broadly r£)unded, and 

 posterior margin short and narrowly rounded. Dorsal-posterior shoul- 

 der angle obtuse. Disk slightly depressed in front of the shoulder. 

 Nepionic shell slightly flattened and marked by rather closely set 

 undulations continuing radially 7 to 9 millimeters. Surface of disk 

 smooth except for growth lines. 



Dimensions.— Tyi^Q—vighi valve (Cat. No. 370831, U.S.N.M.), 

 latitude, 100 mm. ; altitude, 69 mm. ; diameter, 17 mm. 



The new subspecies has a lower and larger shell than Crassatellites 

 meridionalis. Its posterior ext^'emity is less truncated and less de- 

 pressed in front of the dorsal posterior shoulder. The nepionic shell 

 has fewer undulations. This subspecies differs from the new sub- 

 species suii^ensis in having a more inequilateral shell and a shorter 

 radial continuation of nepionic undulations. 



Occurrence. — St. Marys formation, zone 2, U. S. G. S. station 

 3915, Urbanna, Va., type localit}^; U. S. G. S. station 3924, Jones 

 Point, Rappahannock River, Va. 



PHACOIDES (LUCINOMA) CONTRACTUS MURFREESBOROENSIS, new subspecies 



Plate 5, figures 1, 2 



Shell suborbicular, convex, fragile, equivalve, and nearly equi- 

 lateral. Beaks low, apices proximate. Posterior dorsal margin 

 straight and oblique, anterior dorsal margin slightly depressed ; pos- 

 terior, anterior, and basal margins well rounded. Sculpture of 

 rather closely set, nearly erect, slightly beakward reflected, concen- 

 tric primary lamellae, intercalated with about two weak secondary 

 threads. 



Dime7isions. —Ty^Q (Cat. No. 352443, U.S.N.M.), latitude, 28 mm.; 

 altitude, 27 mm. ; diameter of both valves, 15 mm. 



