142 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA, [bull. 100. 



niobasis, to which I was at one time much inclined to refer it, and I am 

 hardly quite sure yet that it may not have to take the name Goniobasis 

 coalvillensis. Many authors refer very similar shells to Chemnitzia, 

 but it has not so large and produced a body volution and aperture as 

 the forms to which Mr. Conrad and Dr. Stoliczka propose to apply 

 that name. If found in any of the Paleozoic rocks, most geologists 

 would refer it to Loxonema of Phillips. Whether or not the nucleus or 

 apex of its spire was covered as in the typical species of Turbonilla, I 

 have been unable to determine. It is a far larger shell, however, than 

 the species upon which that genus was founded. 



" Specifically, this shell seems to be related to Turbonilla spillmani 

 Conrad (Jour. Acad. Nat. Sci., vol. IV, new series, PI. 46, Fig. 28), but 

 its vertical folds or costas are straighter, less crowded, and less numer- 

 ous, while its revolving lines are smaller and more numerous. Its 

 aperture also certainly differs in being decidedly more angular above, 

 and probably somewhat so below. It may likewise be compared with 

 Scalaria mathewsonii Gabb, from Cretaceous rocks of California, from 

 which it differs in having less convex volutions, or less rounded aper- 

 ture, less crowded vertical ridges, and more distinct and coarse revolv- 

 ing lines. 



" Locality and position. — Coalville, Utah ; from below the lowest heavy 

 bed of coal at that locality. Cretaceous." 



The figures of this species hitherto published do not give a correct 

 idea of it, because the specimen 'drawn had lost nearly all of the shell 

 and consequently the transverse costae are less prominent and more 

 broadly rounded than they should be. The examples figured on PI. 

 xxx are from the typical locality and certainly belong to Meek's spe- 

 cies. They show the character of the ornamentation and the extremes 

 of variation in form, but they do not give any additional information 

 concerning the generic relationship of the shell. 



Some fragmentary specimens that apparently belong to the same 

 species were collected from shales in the " third ridge v of the Coalville 

 section, about 1,500 feet above the bed in which the types were found. 



Chemnitzia? sp. 



Turhonilla (Chemnitzia) melanopsis (Con.?) "White, 1876, U. S. Geog. and Geol. Sur. 



West 100th Merid., vol. iv, p. 197, PI. 18, Fig. 10a. 

 Not Turbonilla (Chemnitzia) melanopsis Conrad, 1860, Jour. Acad. Nat. Sci., Phila., 



2nd ser. vol. iv, p. 287, PI. 46, Fig. 35. 



The fragments figured by Dr. White and doubtfully referred to Con- 

 rad's species came from southern Utah. Other similar specimens have 

 since been obtained from the coal-bearing series near the base of the 

 upper Cretaceous in the same region, where it is associated with Glau- 

 coma coalvillensis, Barbatia micronema, and Corbula nematophora. They 

 are too imperfect for specific description, but they are certainly distinct 

 from Turbonilla melanosis, The form is apparently rather short and 



