GEOLOGICAL SURVEY OF THE TERRITORIES. 313 



revolving lines, while others show a few distantly-separated, very slen- 

 der, raised lines. In still others five or six well-defined slender lines 

 may be seen on some of the volutions, and a smaller number of less 

 distinctly-defined ones on the other turns. The arrangement of these 

 lines and their comparative size on different individuals, as well as on 

 different parts of the same specimen, vary much. Usually the upper 

 turns near the apex of the spire appear to be smooth, though this may 

 be partly due to accidental erosion before the shells were imbedded in 

 the matrix. 



Locality and position : Twelve miles southwest of Salina, Kansas ; 

 Dakota Group of cretaceous. Professor B. F. Mudge, collector. 



TURBO MUDGrEANUS, (MEEK.) 



Shell small, turbinate, about as high as wide ; spire moderately prom- 

 inent ; volutions, four and a-half to five, increasing rather rapidly in 

 size, convex ; last one somewhat obliquely flattened below, and laterally 

 compressed or flattened around the middle of the outer side ; suture 

 more or less channeled •, aperture circular ; outer lip thin and oblique ; 

 columella arched and flattened below ; axis imperforate. Surface orna- 

 mented by strong, raised, oblique lines of growth, which are crossed by 

 four equidistant, rather sharp, revolving carinse, 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 (Palse- 

 ont. Fr. Ter. C3ret., t. II, PI. 186 bis, fig. 5, 6), but clearly differs in hav- 

 ing 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 like- 

 wise wants the 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 

 those of the spire. 



The specific name is given in honor of Professor Mudge, of the Kan- 

 sas 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 : Same as last. Professor B. F. Mudge. 



Tertiary species. 



UNIO LEANUS, (MEEK.) 



Shell attaining a medium size or larger, rather thin ; longitudinally 

 ovate, being somewhat less than twice as long as high, with the widest 

 (highest) point in advance of the middle, rather distinctly convex ; an- 

 terior side wider than the other, and regularly rounded ; posterior margin 

 more narrowly rounded, or sometimes obliquely subtruncate above; basal 

 outline forming a broad, semiovate curve, with the most prominent part in 

 advance of the middle ; beaks moderately depressed and placed between 

 one-third and one-fourth the length of the valves from the anterior 

 margin; surface smooth or only showing marks of growth; hinge 

 strong, cardinal teeth prominent, and leaving in internal casts a very 

 profound impression, ranging vertically just behind the anterior muscular 

 scar ; lateral teeth long and straight ; two in the left and one in the right 

 valve. 



