FOSSILS OF THE DEVONIAN. 



129 



limestone, and states that he does not know of its occurrence in the Hamil- 

 ton and Chemung Groups of New York. 



In Europe it has a wide vertical range in the Devonian formation, and 

 its geographic range is very great. 



There appears to be considerable confusion in regard to the relations 

 of this species and P. (P.) Shumardianus of Hall, and also with several 

 European forms that have been identified with it. There can hardly be any 

 doubt of the identity of the specimen figured on plate xiii, figs. 20, 20a, the 

 one given by Murchison in his original description of the species, and the 

 adjoining figures, 19, ly, of the Nevada specimen which is associated in the 

 same layer of rock with specimens which unite it, by a series of examples, 

 with the typical forms of P. (P.) Shumardianus as they occur in the Burling- 

 ton sandstone of Iowa. At present it is not practicable to give the neces- 

 sary illustrations to show the passage from this species to several forms now 

 considered as distinct, but it is anticipated that the opportunity will be af- 

 forded in the future and that larger collections will be accessible from the 

 Devonian of the Rocky Mountain region. 



Formation and localities. Lower, middle, and upper horizons of the 

 Devonian limestone, west slope of County Peak; Rescue Hill; mouth of 

 Packer Basin, and at The Gate northwest of Eureka, Eureka District, 

 Nevada. 



Productus (P.) subaculeatus also occurs in the Lower Carboniferous of 

 the Eureka District. 



Productus (Productella) Shumardianua Hall. 

 Plate xiv, fig. 1. 



Productus snumardianus Hall, 1858. Geol. Eep. Iowa, vol. i, pt. 2, p. 499, pi. iii, fig. 



9; pi. vii, fig. 1. 

 spinulicostce (in part) Hall, 1857. Tenth Ann. Kep. N. Y. State Cab. Nat. 



Hist., p. 173. 

 concentricus Hall, 1857. Tenth Ann. Eep. N. Y. State Cab. Nat. Hist., 



p. 180; Geol. Eep. Iowa, vol. i, pt. 2, p. 517, pi. vii, fig. 3. 

 pyxidatus (partim vel totum) Hall, 1858. Geol. Eep. Iowa, vol. i, pt. 2, p. 



498, pi. 3, figs. 8a-e. 

 Productella shumardiana Hall, 1867. Pal. N. Y., vol. iv, p. 157, pi. xxiii, figs. 6-8. 



With the views expressed in relation to this species, in the remarks on 

 P. (P.) subaculeatus, it is unnecessary to state why they are considered as 



9 O D W 



