OIRTY, NEW CARBONIFEROUS FOSSILS 315 



ably be best to regard it as a distinct variety. In addition to the typical 

 specimen, several other examples have more or less doubtfully been as- 

 signed to this group. 



Chonetes sericeus sp. nov. 



Shell of medium size, a width of 16 mm. being about the maximum observed. 

 Frequently rather transverse with somewhat extended hinge line ; some speci- 

 mens with proportionately greater height and more quadrate shape. 



Convexitj' of ventral valve moderate. In some specimens, this valve is only 

 slightly convex with an inconspicuous beak and presumably a rather high 

 area. Occasionally in specimens of this tjpe, the chief convexity lies towards 

 the margins. In other specimens, the umbonal region is moderately vaulted 

 and the beak fairly prominent. The cardinal spines are rather slender, 

 strongly oblique, and there are probably four or five on each side. 



Dorsal valve like the ventral in shape, varying from flat to gently concave. 



Surface marked by fine radiating lirre of which some 13 to 15' occur in a 

 distance of 2 mm. They are rather sharply defined and crossed by strong, 

 somewhat irregular strire of growth, which over some areas are prominent 

 and sinuous. They are also specially noticeable on the cardinal angles, where 

 the radii are apt to be faint or lacking for a considerable distance. 



Strophalosia subcostata sp. nov. 



Shell small, productiform. Ventral valve strongly ar-^hed; umbo fiattened 

 by attachment. Ears strongly depressed and rather spreading. Sculpture 

 consists of moderately strong, coarse strife of growth, of large spines upon the 

 ears, which spring directly from the surface, and of interrupted cost?e or elon- 

 gated spine bases which end abruptly with the formation of a small spine at 

 the anterior end. 



Dorsal valve unknown. 



Productus inflatus var. clydensis var. nov. 



Shell rather small, often much produced and deeply enrolled. Fold and 

 sinus more or less evanescent. Ears small, subquadrate. 



Surface marked by fine, rigid line, about 16 in 10 mm. In specimens which 

 are much produced, they seem to become evanescent anteriorly. In the ven- 

 tral valve, a cluster of large spines occupies the ears, while a considerable 

 number of smaller ones are scattered over the surface. The visceral area is 

 crossed by transverse wrinkles which tend to be coarse, faint and irregular. 



Productus inflatus var. coloradoensis var. nov. 



? 1890. Productus holiviensis (non d'Orbigny). Nikitin. Com. G6ol. [Russia], 

 Mem., vol. 5, No. 5. p. 57, pi. 1. figs. 4ff, 4ft, 4c. 

 Gschelstufe : Near Moscow, Russia. 

 71902. Productus inflatus (non McChesney). Tschernychew, Com. Geol. [Rus- 

 sia], Mem., vol. 16, No. 2. p. 261. pi. 28. figs. 1-6. 

 Gschelstufe: Ural and Timan Mountains, Russia. 



