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



possessed the delicacy of surface seen in those genera, it might per- 

 haps with more propriety be referred to Aclis or Menestho. The frac- 

 tured lip in some of the specimens has somewhat the appearance of a 

 slight angularity or very small notch at the base of the aperture, but 

 this may be due to the manner in which it is broken ; if not, it would 

 seem to present affinities with the genus Mesalia. It will be readily 

 distinguished from the species I described under the name T. spironema 

 by its less attenuated form and finer and less distinct revolving lines. 

 It is also not nearly so attenuated toward the upper part of the spire 

 as that species. 



" Locality and position. — Coalville, Utah, from the Cretaceous below 

 the heavy bed of coal mined at that place." 



Genus GLAUCONIA Giebel. 



Glauconia coalvillensis Meek (sp.). 



PI. xxvin, Fig. 11 ; PI. xxix, Figs. 1 and 2. 



TurritcUa coalvillensis Meek, 1873, Ann. Rept. U. S. Geol. Sur. Terr, for 1872, p. 502 ; 



White, 1879, idem for 1877, p. 315, PI. 9, Fig. 4ft. 

 Cassiope ivhitfieldi White, 1876, U. S. Geog. and Geol. Sur. West 100th Meridian, vol. 



iv, p. 196, PI. 18, Fig. 1ft. 



Original description of Cassiope whitfieldi : 



u Shell moderately large, elongate-conical, umbilicate; volutions ap- 

 parently about twelve, prominent and prominently angular below the 

 middle of the visible portion, slightly concave from the prominent re- 

 volving angle to the suture below, also very slightly and somewhat 

 irregularly concave from that angle to the suture above. A little be- 

 low the suture there is a rather small, shallow furrow, 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 con- 

 vex, 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 be- 

 tween the two last-named ridges that the hinder edge of each succeed- 

 ing volution joins the preceding one. Umbilicus moderately large and 

 deep; aperture subovate in outline; outer lip sinuate, having abroad, 

 shallow notch above its middle, projecting somewhat anteriorly, and 

 rounded abruptly into the umbilicus. 



" Surface marked by more or less strong undulating lines of growth 

 apparently without small revolving lines. 



" Diameter of the last volution of our largest example, nearly 4J 

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

 not far from 11 centimeters." 



Turritella coalvillensis was originally described from fragments that 

 are more or less eroded and do not show the umbilicus. When better 

 preserved specimens were obtained from southern Utah they were 



