MARYLAND GEOLOGICAL SURVEY 2-il 



open. Surface marked by six strong, elevated, spiral ridges, with flat- 

 tened interspaces, the upper ridge being a little the strongest. These 

 spiral ridges often appear double on the surface, from the effect of weath- 

 ering, but when perfect they are rounded. There are also finer but dis- 

 tinct transverse raised lines, which cross the spiral ridges, and are distinct 

 on the interspaces, but faint or even obsolete on the spiral ridges. Inner 

 margin of the lip faintly marked by depressions corresponding to the 

 spiral lines." Whitfield, 1894. 



Length, 16 mm.; width, 11 mm. 



Occurrence. — Calvert Formation. Church Hill, Plum Point, 3 

 miles south of CJiesapeake Beach. 



Collections. — Maryland Geological Survey, Johns Hopkins University, 

 IT. S. ISTational Museum. 



Family SOLARllD/E. 



Genus SOLARIUM Lamarck. 



Solarium trilineatum Conrad. 

 Plate LYIII, Figs. 3a, 3b, 3c. 



Solarium trilineatum Conrad, 1841, Proc. Acad. Nat. Sci. Phila., vol. i, p. 31. 

 Solarium trilineatum Conrad, 1842, Jour. Acad. Nat. Sci. Phila., vol. viii, 1st ser. 



p. 186. 

 Solarium trilineatum Conrad, 1843, Proc. Nat. Inst., BulL ii, p. 181. 

 Architectonica {Phillipia) trilineata Conrad, 1863, Proc. Acad. Nat. Sci. Phila., vol. 



xiv, p. 566. 

 Architectonica {Phillipia) trilineata Meek, 1864, Miocene Check List, Smith. Misc. 



ColL (183), p. 17. 

 Architectonica trilineata Conrad, 1868, Amer. Jour. Conch., vol. iii, p. 260 pi. xx 



fig. .5. 

 Solarium trilineatum Dall, 1893, Trans. Wagner Free Inst. Sci., vol. iii, pt. ii 



p. 337. 

 Solarium trilineatum Harris, 1893, Amer. Jour. Sci., ser. iii, vol. xlv, p. 25. 



Description. — ''Depressed, conical; whirls with obsolete spiral lines, 

 and fine transverse striae, an impressed line below the suture ; whirls car- 

 inated at base; suture deeply impressed; periphery carinated, and mar- 

 gined above and beneath by a carinated line; umbilicus profound, crenate 

 on the margin, and with a submarginal impressed line, stride radiating 

 from the umbilicus, becoming obsolete towards the periphery. Width ^ 

 inch." Conrad, 1841. 

 16 



