598 Systematic Paleontology — Upper Devoniax 



catious, fold aud sinus covered with elongated pustules or spine bases and 

 the plication generally marked liy a fine median line. 



Allied to Spirifer marcyi but distinguished therefrom in its high erect 

 cardinal area, shorter hinge and fewer plications is the species Spirifer 

 asper Hall, originally described from a middle Devonian horizon in Iowa 

 (Eockford and other localities) but also known to occur in the Hamilton 

 fauna of New York. 



To both of these shells some of the s})ecimens from the ^Maryland 

 Chemung are closely related. They show the long lateral slopes of S. 

 marcyi and the largest of them indicating full growth bear 30 plications, 

 which are fine, simple and not crossed by concentric growth lines. The 

 surface is distinctly granulose, or sometimes pitted over the fold and 

 sinus and along the plications. The latter are narrower than in t?. 

 marcyi and have more nearly the width of the separating furrows. In 

 specimens from the Chemung the cardinal area is high and erect, in 

 which respect the shell is more like Spirifer asper. In individuals from 

 the Parkhead the area is not so high and the expansion of the shell is 

 more normal. The length of the larger shells along the hinge is 50-60 

 mm. The unusual occurrence of a Spirifer of this type in the upper 

 Devonian of the interior pro\dnce, a fact not hitherto noted in this region, 

 is worthy of s^^ecial record as another instance of the survival of Hamil- 

 ton specific types into later faunas which is so emphatically illustrated 

 by the fauna of the Ithaca beds. We have, tlierefore, designated the shell 

 by the mutational term superstes. 



This recurrent Hamilton species is abundant in the more westerly 

 exposures of the Parkln-ad and in the up])er Tropidolepiiis zone of the 

 Chemung. The variety svpcrsies is best characterized in the higher zone. 



Occurrence. — Jenkixgs Foumation^ Chemung Member. Upper 

 Tropidolepius zone, 2% miles south of Round, West Virginia; iSTational 

 Eoad, Polish Mountain above 6th turn; Town Creek, 2691 common; 

 National Eoad, on Green Eidge, 2690 abundant. Parkhead ]\Iember. 

 Williams Eoad, east of Cumberland, 1466 abundant; Eocky Eun abun- 

 dant; road 1 mile north of Eocky Eun; Williams Eoad, on Polish Moun- 

 tain, 1660 abundant; National Eoad, 1196, 1625; 2 miles north of mouth 



