460 NON-MARINE FOSSIL MOLLUSCA. 



genus Goniobasis. It has also been considered doubtful by many natu- 

 ralists whether any one of the fossil species that have been found in the 

 rocks of North America, ought to be referred to the family MclaniidoB. 

 The five or six following species, however, are in this article provsionally 

 referred to that family ; two because they are at present believed to 

 strictly belong there; and the others partly because of their apparent 

 affinities in that direction, and partly because they seem to be not 

 properly referable to the Ceriphasiidre. They are all interesting shells, 

 embracing three distinct types, two of which, at least, are not known 

 to have living representatives; but two of the species, while they appear 

 to have no generic representative living in North America, seem to be 

 referable to true Melania of Old World type. 



One of the species last referred to is Melania wyomingensis Meek, 

 (M. larunda White,*) which has been found on both sides of the Itocky 

 Mountains in Southern Wyoming and Northern Colorado. Figures of 

 this fine species are given on Plate 26. 



The other species, which appears to be a true Melania, is M. claiborn- 

 ensis Heilprin, from the marine Eocene deposits of Alabama.t It is 

 represented on Plate 28. 



In Southern Wyoming Mr. Meek also obtained from the Laramie 

 strata a form which he described under the name of Melania insculpta.$ 

 It seems to be nearly related to M. wyomingensis^ but differs from it in 

 wanting its prominent subspinous ornamentation. This species has 

 also been found in the Laramie strata east of the Eocky Mountains in 

 Colorado, the specimens figured on Plate 26 having been collected in 

 the valley of South Platte Eiver. 



There occurs somewhat abundantly in the Bear Eiver Laramie beds 

 of Southwestern Wyoming and the adjacent parts of Utah a shell 

 which Mr. Meek first referred to Melania^ but to which he afterward 

 gave the new generic name of Pyrgulifera, describing it under the 

 name of Pyrgulifera humrosa. It is illustrated on Plate 6. Mr. Meek 

 placed this shell among the CeriphasiidaB or American Melanians, but 

 as it seems to differ quite as widely from the typical forms of that 

 family as it does from the true Melanians, I here place it provisionally 



* An. Rep. U. S. Geol. Sur. Terr, for 1878, Part I, p. 95, pi. 28, fig. 6. 



t Although the associates of this shell are all marine, it is given a place in this 

 article hecause Melania is generally regarded as a fresh-water genus. In this connec- 

 tion, however, it is proper to remark that among certain fossil faunae shells undis- 

 tinguishable from Melania are found associated with marine forms. (See Professor 

 Heilprin's description and remarks, Proc. Acad. Nat. Sci., Phila., 1879, p. 214.) M. 

 wyomingensis and M. insculpta have also been found in such association with Ostrea 

 and Anomia, as to indicate that they all lived and flourished together in the same 

 waters, which were certainly in some degree saline, or the Ostrea and Anomia could 

 not have existed there. 



* See An. Rep. U. 8. Geol. Sur. Terr, for 1878, Part I, p. 94, pi. 20, fig. 4. 



$ For diagnosis of this genus, and description and figures of the species, see U. S. 

 Geol. Sur. 40th Parallel, vol. iv, p. 146, pi. 17, fig. 19. 



