ARNOLD — THE PALEOMTOLOOY AND STnATIGKAril Y OF SAN PEDIIO. 107 



159. Melampus olivaceus Cdrpc.nlcr. 



Melampns olivaceiis Qvv.. , Mazatlan Cat., No. 235; Brit Assn. Ript., 1863, p. 647. Cooi'ER, 71I1 

 Ami. Rept. Cal. St. Min., 18SS, p. 250. Keep, West Coast Shells, p. 124, fig. 113, 

 1892. Williamson, Proc. U. S. Nat. Mus., Vol. XV, 1892, p. 196. 



Shell small, thin, pyriform; spire solid, conical, barely elevated; whorls four or live, flat; 

 l)ody-whorl comprises most of shell, slightly angulated above; suture appressed, wavy; aperture 

 lonj;, narrow, rounded anteriorly; outer lip thin; inner lij) incrusted, and with one prominent plica- 

 lion, antl sometimes one or two more smaller ones; jne prominent plication on columella; umbilicus 

 subperforate. 



Diviensians. — Long. 12 mm.; lat. 9 mm.; aperture 9.5 mm. 



Somowliat res^emblcs a small, thin, depressed Conns cnlifornicns. 

 Found in all of the lower and upper San Pedro localities. Also fdiiiui in I lie 

 Pleistocene at Twenty-sixth Street, San Diego. 



Living. — Salinas River to Mazatlan (Cooper). 



Pleistocene. — San Diego (Cooper): San Pedro; San Diego (Arnold). 



Pliocene. — San Diego well (Dall). 



Superfamily PETROPIIILA. 



Family XLI.X. ( I A DINIID.E. 



Gcnii.s Gadinia lird;/. 



SIkU obiiciuciy conical; muscular impression horseshoe-sliaped, the right side shortest, 

 terminating at the siphonal groove. 



Gadinia a I'm Gray is a characteristic species. 



160. Gadinia reticulata Souerhij. 



Mourclia nticiilala SliV., Proc. Zool. .Soc, 1S35, p. 6. 



Gadinia reticulala Sbv., H. & A. Adams, Gen. Rec. Moll., Vol. I, p. 463, 1853. Cpr., Brit. As.sn. 



Rept., 1863, p. 666. Dall, Am. Jour. Conch., Vol. VI, i87i,p. 11, PI. II, figs, i to 9; 



PI. IV, figs. I, 2 and 3. Keep, West Coast Shells, p. 98, fig. 83, 1892. Williamson, 



Proc. U. S. Nat. Mus., Vol. XV, 1892, p. 196. 

 Ro'icel/ia sp. Cpr., Brit. Assn. Rept., 1863, p. 651. 

 Gadinia ( Roivellia) radiata Cooper, Gabm, Proc. Cal. Acad. Sci., Vol. III. 1865, p. 188. Cooper, 



Geogr. Catal. Moll., p. 24, No. 460, 1867. 

 Roiucllia radiata Cooper, Am. Jour. Conch., Vol. VI, 1871, p. 319. 

 Gadinia radiala Cooper, Dall, Am. Jour. Conch., Vol. VII, 1872, p. 192. 

 Gadinia reticulata van radiata Cooper, Bull. No. 4, Cal. St. Min. Bureau, 1894, p. 26. 



Shell conical; ape.x central, smooth, bliiiU; surface sculptured by numerous rounded, 

 radiating ridges, made somewhat nodose by concentric, elevated lines of growth; aperture slightly 

 ovate; inner surface smooth; lip smooth, effuse; color white. 



Ditn€7isio7is. — Long. 15 mm.; lat. 14 mm.; alt. 5 mm. 



Somcwliat resembles Acmren mitra, hut is more depre.ssed, has a less acute 

 apex, and is sculptured radially. One specimen found in upper San Pedro series of 

 San Pedro. 



