196 (JRETACEOUS PERIOD. 



Genus CASSIOPE Coquand, 18G5. 



Cassiope Whitfieldi White. 



Plate XVIII, fig. 1 a. 



Cassiope WhUjieldi, White, 1874, Expl. & Surv. west 100th Merid., Prelim. Eep. luvert. 



Foss., 27. 



Shell moderately large, elougate-conical, umbilicate ; volutions appar- 

 ently about twelve, prominent and prominently angular below the middle 

 of the visible portion, slightly concave from the prominent revolving angle 

 to the sutm-e below, also very slightly and somewhat uTegularly concave 

 from that angle to the suture above. A little below the su.ture there is a rather 

 small, shallow frirrow, with its borders above and below raised into more or 

 less distinct revolving ridges. Upon the under side of the last volution, 

 which is rather strongly convex, there are three small revolving ridges, one 

 of them bounding the umbilicus ; the other two are placed near each other 

 above the middle of the space, and are continuous to the apex of the shell. 

 It is between the two last-named ridges that the hinder edge of each 

 succeeding volution joins the preceding one. Umbilicus moderately large 

 and deep ; aperture subovate in outline ; outer lip sinuate, having a broad, 

 shallow notch above its middle, projecting somewhat anteriorly, and rounded 

 abruptly into the umbilicus. 



Sm-face marked by more or less strong undulating lines of growth, 

 apparently without small revolving lines. 



Diameter of the last volution of oui- largest example, nearly fom- and 

 a half centimeters ; the full height of the same, when entire, must have been 

 not far from eleven centimeters. 



This shell has nearly the general aspect of Turritella Mortoni Conrad, 

 but the presence of an umbilicus separates it generically from that shell. 



Dedicated to Mr. R. P. Whitfield, the accomplished paleontologist of 

 Albany, New York. 



Position and locality. < — Strata of the Cretaceous period ; at the head of 

 LeVerken Creek, and also in Pace's Canon, Utah. 



