300 UNITED STATES GEOLOGICAL SURVEY OF THE TERRITORIES. 



»liiru:inl:i Kndgeana, Meek. 

 Plate 2, figs. 9, a, ft. 

 Turbo Mudijtanws, Meek (1>-7I), Hayden's Report U. S. Geol. Survey of the Territories, :U:3. 



Shell rather large, turbinate, about as high as wide; spire moderately 

 prominent; volutions tour and a half to tive, increasing rather rapidly in size, 

 convex, last one somewhat obliquely flattened below and above, and laterally 

 compressed or flattened around the middle of the outer side, at the base ol 

 which it is angular; suture more or less channeled; aperture circular; outer 

 lip thin and oblique; columella arched and flattened below; axis imper- 

 forate ; surface ornamented by strong, raised, oblique lines of growth, which 

 are crossed by four equidistant rather sharp, revolving carina-, only three of 

 which are seen on the volutions of the spire. 



Height, 0.66 inch; breadth, about 0.64 inch; divergence of slopes of 

 the spire, about 75°. 



This shell is evidently related to Turbo tricostatus, d'Orbigny (Paleont. 

 Fr. Terr. Cret., II, pi. 1S6 bis, figs. 5, 6), but clearly differs in having its spire 

 decidedly more depressed, and in having four revolving carinse on its body- 

 volution instead of only three. Its body-whorl is also more rounded, in 

 consequence of its greater convexity on the upper side, which also imparts a 

 more rounded outline to its aperture. It likewise wantslhe small umbilicus 

 said to exist in d'Orbigny's species, and does not show the lower carina of the 

 body-turn above the suture on (hose of the spire. In the entire absence of 

 any umbilical perforation it differs from the usual characters of the genus 

 Margarita; but Mr. Dall informs me that there are some existing northern 

 species that are entirely without any traces of an umbilicus. 



The specific name was given in honor of Professor Mudge, of the Kansas 

 State Agricultural College, to whom I am indebted for the typical specimens 

 of this, as well as of the other species here described from the same locality. 



Locality and position. — Twelve miles southwest of Salina, Kansas; 

 from the Dakota group of the Upper Missouri Cretaceous. Prof. B. F. Mudge. 



Genus MARGARITA LLA, M. & H. 



SynoiL— Solarium (sp.). ol' several authors, hut not of Lamarck. 



Margaritella, Meek ami Hayden (1860), Proc. Acad. Nat. Sei. Philad., XII, 423.— Meek (1864), 

 Smithsonian Cheek-List N. Am. Cret. Fossils, IB (not Gahh (1864), Paheont. Gal., I, 

 118, and ib., II, 172; or Stoliezka (1870), Palwont, Ind., II, 367). 



Etijm. — Margarita, a pearl (diinin.). 



Type. — Solarium flexislriatnm, Evans and Shnmard. 



Shell subdiscoidal or nearly lenticular, thin ; nacre of interior bright; 

 umbilicus large, deep, and entirely without crenate margins; volutions nar- 



