GEOLOGICAL SURVEY OF THE TERRITORIES. 503 



spire being soinewbat below tbe middle, wbere tbey are angular; sur- 

 face below tbe angle llattened, or a little concave, and sloping rather 

 abruptly inward and downward to the suture, whde above, to near the 

 upper margin, where there is a shallow revolving concavity a little below 

 the suture, it is convex; last volution probably biangular around the 

 middle; suture well detined ; aperture unknown. Surface ornamented 

 by rather obscure revolving ridges, about tive of which may be counted 

 on each volution of the .spire, one being at the lower margin immediately 

 above the suture; another, which is also the largest, occupying the most 

 l>rominent angular i>art of the whorl ; and above this three others 

 occur, one being above the revolving concavity, and at the immediate 

 upper margin ; lines of growth obscure and making a strong backward 

 curve in crossing the middle of the volutious. 



I have not seen specimens of this line species sufficiently well pre- 

 served to be able to give accurate measurements, though those I 

 Lave had au opportunity to examine indicate a length of not less than 

 two iuches aud a fraction, and a breadth of 0.93 inch. The angle of its 

 spire, as taken from near the middle of a large specimen, imperfect at 

 both extremities, measures about 23°, while smaller individuals, com- 

 posed of live or six of the upper volutions, show au angle of nearly 30°. 

 It is, therefore, evidently a large, robust species, that increases rather 

 rapidly in size from the apex. 



Specimens of this species were brought in by Dr. Hayden a year or 

 two since, and were supposed by me probably to belong to T. Martlne- 

 Z€7isis, Gabb, to which it is evidently related in size, form, aud general 

 appearance. Since seeing the California State collection, at San Fran- 

 cisco, during the past summer, however, and some additional collections 

 from Coalville, I have become satisfied that the Utah shell is distinct 

 from Mr. Gabb's species. In this opinion Mr. Gabb also concurs, after 

 seeing our specimens. The most obvious diflerence is that our shell 

 Las the volutious constantly convex above the angle, and below the 

 revolving concavity near the upper part, while in the California species 

 the upper slope of the volutions is regularly concave from the u[)j)er 

 margin to the angle. Better specimens would doubtless show other 

 differences. 



Locality and position. — ^Coalville, Utah. From the Cretaceous, beneath 

 the lower heavy bed of coal. 



TUREITELLA SPIRONEMA, Meek. 



Shell rather small, or scarcely fittaiuiug a medium size, elongate coni- 

 cal ; volutions about titteen, increasing very gradually in size, mod- 

 erately convex, last one rounded m the middle; aperture apparently 

 ovate; columella rather regularly arcuate. Surface ornamented by 

 squarish, rather regular revolving thread like lines, with nearly equal 

 furrows between ; about five to seven or eight of the lines and furrows 

 are seen on each of the turns of the spire, and nearly twice as many ou 

 the body whorl, where those below the ujiddle become abruptly smaller 

 and more crowded than those above; lines of growth obscure and gently 

 arched in crossing the volution; suture moderately distinct. 



Length of the largest specimen found, 0.82 inch ; breadth of body volu- 

 tions, 0.23 inch; spire nearly regular; divergence of its slopes, about 17'^. 



There is a slightly polished, appearance of the surface of this shell 

 that is not often seen in the true TnrriteUa, and gives origin to sou)e 

 doubts whether it maj^ not belong to some group allied to Aclis or Me- 

 nestho. As iii size aud general appearance, however, it seems to cor- 



