162 Systematic Paleontology — Middle Devonian 



Occurrence. — Eoimney Formation, Onondaga Member. W. Va. Cent. 

 E. E. cut at 21st Bridge. Marcellus Member. Williams Eoad, 3I/2 miles 

 southeast of Cumberland. Hamilton Member. East bank Evitts Creek 

 below Wolfe Mill; Williams Eoad about 1/4 ^^i^e east of the Queen City 

 Hotel. 



Collections. — Maryland Geological Survey; Xew York State Museum; 

 American Museum of Natural History; U. S. National Museum. 



Genus PRODUCTELLA Hall 

 PrODUCTELLA cf. SPINULICOSTA Hall 



Plate XIII, Fig. 17 



Productus spinuHcostus Hall, 1857, Tenth Rep. N. Y. State Cab. Nat. Hist., 



p. 173. 

 Productella spinulicosta Hall, 1867, Pal. N. Y., vol. iv, p. 160, pi. xxiii, figs. 



6-8, 25-34. 

 Productella spinulicosta Hall and Clarke, 1892, Pal. N. Y., vol. viii, pt. i, pL 



xvii, figs. 3-6. 

 Productella spinulicosta Schuchert, 1897, Bull. U. S. Geol. Surv., No. 87, p. 318. 

 Productella spinulicosta Clarke, 1903, N. Y. State Mus., Bull. 65, p. 292. 

 Productella spinulicosta Grabau and Shinier, 1907, N. Am. Index Fossils, vol. 



ii, p. 241, figs. 293c, d. 



Description. — "Shell broad, semielliptical or somewhat orbicular; 

 hinge-line generally a little less than the greatest width of the shell. 

 Ventral valve varying in shells of different size, from moderately to 

 extremely gibbous in the middle, with the beak strongly incurved. Dorsal 

 valve moderately concave in its upper part, and becoming more concave or 

 arcuate towards the front. Surface marked by fine strong concentric 

 striae, which are sometimes crowded and wrinkled on the body of the 

 shell. There are several rows of interrupted ridges or spine-bases, which 

 in entire specimens support slender spines. The ears are strongly 

 wrinkled, and support a row of four or five spines just below the hinge- 

 line." Hall, isn7. 



A small and somewhat imperfect ventral valve of Productella was 

 found in the Maryland collection which at least may be compared with 

 this species and probably belongs to it. The valve is strongly gibbous in 

 the central part. There is no tmncation of the umbo or evidence of its 



