190 PALEONTOLOGY OF THE EUEEKA DISTRICT. 



Genus LOXOKEMA Phillips. 



Casts of five species of spiral univalves occur in the lower fossiliferous 

 beds of the Devonian limestone. They are in such a condition of preserva- 

 tion as to render it difficult in the absence of surface-markings to determine 

 their relations, although they evidently belong to the genus Loxonema. 

 Professor Hall met with a group of species in the Upper Helderberg Group 

 of the State of New York in a similar condition, and assigned specific names 

 to those differing widely in form and proportions from those already de- 

 scribed so as to be distinguished by these characters alone. This course is 

 the only one to pursue with such meager and unsatisfactory material when 

 it is desirable to specify the different forms, and as this is the case with the 

 Nevada species, two of the five are described and referred to Loxonema, and 

 a descriptive note given with each of the remaining three, one of which is 

 provisionally referred to Loxonema subattenuata, of the Upper Helderberg 

 Group of New York. 



Loxonema Eurekensis, n. sp. 

 Plate xvi, fig. 8. 



Shell turretiform, elongate, robust; spire somewhat rapidly ascending, 

 angle of divergence from the apex, 25. Volutions, eleven or more in a 

 specimen of 110 mm in length, slightly convex, and very gradually expand- 

 ing from the apex. 



Surface unknown. 



Formation and locality. Lower horizon of the Devonian limestone; 

 divide at the head of the Reese and Berry Canon, Eureka District, Nevada. 



Loxonema nobile, a. sp. 

 Plate xvi, fig. 9. 



Shell robust, elongate, turretiform; spire rapidly ascending, angle of 

 divergence from the apex, 15. Volutions regularly increasing from the 

 apex, slightly convex ; the three lower volutions have a united length of 



50 mm . 



