MA i;VI. A \ I) (li:nl,()(;|('Al, sritVKY IG') 



Lcii,L;tli. 10 iimi.; lici.LiliK T mm. 



Otciirrciicr. — >>' \ \.i l;\l()^ I'(ii;ma rin\. y.:\>-\ ami west nf I'mt Tnliiicco, 

 Woodstock. I'dpcs Creek, '! \ miles alxtve I'Dpes Creek, Head of Nanjeinoy 

 Creek, I'liper Marllimo (deej) iiil near ( lie.-apcakc l^)eacli K. R. station), 

 1 mile soulheasl of Piscataway. Mills llridjie? AqiTA Formatiox. 



( ilvilKMll. 



Colh'clloii. — ^lai-ylaiitl ( lenlooieal Siii'vey. 



Family SOLENIDAE. 



Genus SOLEN Linne. 

 SOLKX LISBONENSIS (?) AldrJcll. 



Plate XXXIII, Fig. 1. 



Solen lisbone7isis Aldrich, 1886, Bull, i, Ala. Geol. Surve3', p. 37, pi. iv, fig. 4. 



Solen sp. Harris, 1897, Bull. Amer. Pal. No. 9, p. 66, pi. xiv, lig. 9. 



Solen (Plectosolen) linhoneiisis Dall, 1900, Trans. Wagner Free Inst. Sci., vol. iii, pt. v, 



p. 953. 

 (.^) Solen {Plectosolen) UxboneusLs var. abrii.ptus Dall, 1900, Trans. Wagner Free Inst. 



Sci., vol. iii, pt. v, p. 953. 



Description. — ''Shell linear, nearly straight; posterior siibtrimcate; 

 anterior obliquely rounded with a depressed space behind running to the 

 beaks; lines of growth prominent, bending at right angles along a line 

 running obliquely from the beaks to the junction of the posterior and 

 ventral margins. Anterior widely gaping." Aldrich, 1886. 



The references given above are the only records we have of the occur- 

 rence of this genus in the Eocene of Eastern Xorth America. The two 

 specimens from the Potomac Eiver are both imperfect and neither shows 

 any characters upon which they can be specifically separated from 

 S. Ushoiiensis. The lines of growth on our specimens do not bend quite 

 as sharply as they do in Aldrich's figure. In this respect they are more 

 like the figure published by Professor Harris. Our specimens are 

 smaller than either of those figured from Alabama. In the publication 

 above noted, Dr. Dall describes a variety ahruptus under S. lishonensis. 

 This differs from our form even more than the typical S. lishonensis 

 does. 



