582 Systematic Paleoxtology — Upper Devoxiax 



Ou tlie interior the ventral valve shows a ■\vell-marked pedicle cavity and 

 dental lamellae and in hoth valves the mnscle scars are all obscure. 



Length 24 mm.; Midtli 25 mm. 



The single large ventral valve here tignred pertains to an individual 

 which in its plicated sides and multiplicate sinus comes within the limits 

 of the characters assigned to this species. This specimen alone is, how- 

 ever, insufficient to finality determine this identity. 



Liorln/nrJnis multkostum is a common species in the Hamilton fauna 

 of New York and passes into the Ithaca fauna above. There is no record 

 of its higher range in that State. 



Occiivrence. — Jennings Formation, Parkhead ? Member. The 

 single specimen is from l)locky argillaceous layers on the west side of 

 Green Ridge 5 miles west of Piney Grove, Garrett County. 



Collection. — Maryland Geological Survey. 



LlORHYNCHUS GLOBULIFORME (VaUUXem) 



Plate LIV, Figs. 10-16 



Atrypa glohuliformis Vanuxem, 1842, Geology of N. Y., Rept. on the 'id 



Dist., p. 182, fig. 2. 

 Leiorhynchus globnliforvTis Hall, 1867, Pal. of N. Y., vol. iv, p. 364, pi. Ivii, 



figs. 26-29. 

 Leiorhynchus globutifovmis Hall and Clarke, 1894, Pal. of N. Y., vol. viii, 



pt. ii, pi. lix, figs. 23-27. 



UcscriiAion. — Shell suborbicular, rotund. Ventral valve convex over 

 the umbo, depressed anteriorly : dorsal valve ventricose. . Median fold and 

 sinus obscure. Three or four ribs are ^Dresent on fold and sinus but the 

 lateral slopes are smooth or but obscurely plicate. Usually in casts, of 

 which dorsal valves are characterized by the elongate vaginate muscular 

 scar divided by a narrow median septum. 



This shell abounds in and is highly characteristic of the Ithaca fauna 

 of central New York. 



Length 15 to 20 mm.; width 20 mm. 



This species is distinguished by its convexity and by its muscular 

 markings. It is one of the most aluindant and characteristic species of 

 the Ithaca fauna. 



