684 Systematic Paleontology — Upper Devonian 



anteriorly iu passing over sides and posteriorly in passing over dorsal and 

 ventral margins. 



Length 28 mm.; greater diameter aperture 22 mm., lesser diameter 

 9 mm. 



This species is quite distinct from any other form known to the author. 

 It may be somewhat distorted, although shells of other species associated 

 with it do not appear to be compressed. 



Occurrence. — Jennings Formation, Chemung Member. Upper 

 Tropidoleptus zone, ? near Pennsylvania-Maryland state line, west of 

 Green Eidge. 



Collection. — Maryland Geological Survey. 



Platyceras sp. 



Description. — Shell curved, very abruptly contracted at apex which is 

 small. Shape of aperture unkno-wn. 



This shell appears to be of the type of P. attenuatum of the Hamilton 

 of New York. A single specimen only has been seen, which is too im- 

 perfect for illustration. 



Occurrence. — Jennings Formation, Chemung Member. Upper 

 Tropidoleptus zone ? near Pennsylvania-Maryland state line west of Green 

 Eidge. 



CollecHon. — Maryland Geological Survey. 



Genus DIAPHOROSTOMA Fischer 

 DiAPHOROSTOMA LINEATAUM (Conrad) 



Plate LXX, Figs. 17-19 



Platyostoma lineata Conrad, 1842, Jour. Acad. Nat. Sci., Phila., vol. viii, p. 



276, pi. xvii, fig. 7. 

 Platyostoma Hneata Hall, 1876, Illustrations of Devonian Foss., Gastropoda, 



pi. ix. 

 Platyostoma lineata Hall, 1879, Pal. of N. Y., vol. v, pt. ii, p. 21, figs. 1-21. 

 Diaphorostoma lineata Grabau and Shimer, 1909, Index N. Araer. Foss., 



vol. i, p. 680, fig. 953. 



Description. — " Shell subovate, approaching to subglobose. Spire 

 elevated above the body whorl, though varying in degree; in some ex- 

 treme varieties, on the same plane or below the outer volutions. The 



