234 PROCEEDINGS OF THE ACADEMY OF [1888, 



radiating strire, and between the two extremes every degree of 

 gradation occur associated, it is questionable whether the variety 

 Icevis M. and AV. can be considered as having even the value of a 

 variety ; but is to be regarded rather as an individual and not a. 

 varietal difference. 



Solenomya soleniformis Cox. 



Solenomya solenlfonnis Cox, 1857. Geol. Sur. Kentucky, vol. III,, 

 p. 573. 



At the Giant mine the form which is here referred to the species 

 described in the Kentucky Geological report, vol. Ill, p. 573, is not 

 common ; it is considerably larger than that figured by Cox, but 

 otherwise corresponds in all other observable particulars. It is by 

 far the largest lamellibranch yet found at Des Moines, but the shell 

 is very thin and easily detached from the matrix. 



GASTEROPODA. 



Dentalium meekianum Geinitz. 



Dentalmm meekianum Geinitz, 1866. Carb. und Dyas in Ne» 



braska, p. 13. 

 Dentalium meekianum f Meek and Worthen, 1873. Geol. 111., 



vol. V, p. 590. 

 This species is represented by numerous specimens, but none of 

 them having both extremities perfectly preserved. The ornamenta- 

 tion in some of the specimens is well preserved, in others it is obsolete, 

 and a few are perfectly glabrate. 



Dentalium annulostriatum Meek and Worthen. 



Dentalium f annulostriatum Meek and Worthen, 1870. Proc. 



Acad. Nat. Sci. Phila., p. 45. 

 Dentalium f annulostriatum Meek and Worthen, 1873. Geol. 111.,, 



vol. V, p. 589. 

 This species is represented by six specimens ; in four of these the 

 charactei'istic annular costre are very prominent and the furroAVS 

 separating the costse are correspondingly quite deep. 



Bellerophon percarinatus Conrad. 



Bellerophon percarinatus Conrad, 1842. Jour. Acad. Nat. Sci. 



Phila., vol. VIII. 

 Bellerophon percarinatus Meek, 1872. U. S. Geol. Sur. Nebraska, 



p. 227. 

 Rather common and in a fine state of preservation. It is associa- 

 ted with the two other congeneric species here mentioned. 



