150 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA, [bull.106. 



TRITONHD^E. 



Genus TRITONIUM Link. 



Tritonium kanabense n. sp. 

 PI. xxxi, Fig. 12. 



Shell small, slender, fusiform, with six or seven rounded whorls, of 

 which the last is somewhat inflated and below abruptly contracted into 

 the short canal. Surface ornamented by very prominent narrowly 

 rounded transverse costae, of which there are about ten on the last 

 whorl, crossed by strong elevated revolving lines, alternating with faint 

 lines on the later whorls. There are also a few strong varices on the 

 spire, representing the outer lip at various stages of growth. 



The canal is short and somewhat bent and the aperture is ovate in 

 outline. The outer lip is strongly dentate within and the inner lip has 

 a thin callus. 



Length of the type specimen, which is incomplete at both extremities, 

 2imm. greatest breadth, 10 mm . 



Locality and position. — About 350 feet above the base of the Creta- 

 ceous section at Upper Kanab, Utah. Collected by Mr. C. D. Walcott. 



FUSID^E. 

 Genus FUSUS Lamarck. 



Fusus siiumardi H. & M. 



PI. xxxi, Fig. 13. 



Fusus siiumardi Hall and Meek, 1856, Mem. Am. Acad. Arts, and Sci., vol. v, 2d ser., p. 

 391, PL 3, Fig. 6; Whitfield, 1880, Geol. Black Hills of Dakota, p. 424, PI. 12, Figs. 

 • 7 and 8. 



Whitfield's description is as follows: 



u Shell small, with a moderately elevated spire and rather short 

 rostral beak; volutions about six, strongly ventricose, and marked by 

 comparatively strong, slightly oblique, vertical costae or folds, which 

 are directed forward on the lower part of the upper volutions and again 

 recurved below, as seen on the body whorl, and also by finer stria* of 

 growth between the folds. The folds are crossed by numerous elevated 

 revolving lines, with wider interspaces; suture well marked and dis- 

 tinct; aperture obliquely ovate, obtusely pointed above, and continued 

 below into the short, narrow, rostral canal; columellar lip slightly" 

 thickened, but without visible folds or plaits. 



" The specimen used is imperfect at both extremities and much of the 

 surface shell removed; enough remains, however, to furnish the specific 

 characters. The species may possibly belong to Mr. Meek's genus 



