FOSSILS OF THE DEVONIAN. 131 
rocks of Belgium, a new specific designation is given in honor of the origi- 
nal discoverer of the species 
Formation and localities.—Lower and upper horizons of the Devonian 
limestone, west slope of County Peak, and Rescue Hill, Eureka District, 
Nevada. 
Productus (Productella) navicella Hall. 
Plate xiii, fig. 9. 
Productus navicella Hall, 1857. Tenth Ann. Rep. N. Y. State Cab. Nat. Hist., p. 172. 
Productella navivella Hall, 1867. Pal. N. Y., vol. iv, p. 156, pl. xxiii, figs. 1-3, 9-11. 
The specimens referred to this species from the Upper Helderberg and 
Hamilton Groups of New York are distinguished by their narrow, elon- 
gate form, extreme areuation, and strong costz on the lower half of the 
shell that are extended upward as little ridges formed by the spine bases. 
The specimens representing the species in Nevada are a little more elongate 
than the average of the New York forms, and the radiating costee are some- 
what stronger, otherwise the two are identical. 
Formation and locality—Lower horizon of the Devonian limestone, 
south ridge of Atrypa Peak, Eureka District, Nevada. 
Productus (Productella) truncatus Hall. 
Plate xiv, fig. 2. 
Productus truncatus Hall, 1857. Tenth Ann. Rep. N. Y. State Cab. Nat. Hist., p. 171. 
Strophomena pustulosa Hall, 1843. Geol. Rep. Fourth District New York, p. 18. 
Productella truncata Hall, 1867. Pal. N. Y., vol. iv, p. 160, pl. xxiii, figs.12-24. 
Not Productus pustulosus Phillips. 
This pretty little species occurs in the Lower Devonian beds, and pre- 
sents the characters of the specimens from the Marceilus shale of New York. 
In his remarks on this species, Professor Hall states that, on the author- 
itv of M. de Verneuil, Strophomena pustulosa, a species founded apparently 
on a dorsal valve of this species, has been referred to Productus (Stropha- 
losia) Murchisonianus M. de Koninck, which is likewise regarded as iden- 
tical with’ the species Professor Hall described as Productus Shumardianus. 
Professor Hall has shown that P. (P.) truncatus possesses features not ob- 
