466 Systematic Paleontology 



" Leaves large, coriaceous or subcoriaceous, broadly deltoid, more or 

 less distinctly three-lobed, with obtuse divisions, and borders entire 

 or undulate ; nervation palmately 3 to 5 nerved, from a peltate or subpel- 

 tate, truncate or subcordate base; primary veins craspedodrome, their 

 points joining the borders of the lobes, but their divisions following 

 along them by a series of curves upon each other, or of multiple festoons, 

 as seen in the leaves of the present Menispermum canadense especially. 

 The divergence from this last type is marked in one species only, whose 

 nervation agrees with that of Menispermum (Cocculus) caroUnum," etc. 



The craspedodrome character of the venation or the lobate character 

 of the lamina cannot be insisted upon since Lesquereux and others have 

 referred a number of camptodrome and entire forms to this genus. 

 Later exploration in the Dakota sandstone enabled Lesquereux and 

 others to characterize five additional species from this horizon, one of 

 which has been reported from the Coastal Plain. Heer has described 

 two species from the Atane beds of G-reenland, one of which extends 

 southward to the Earitan. of New Jersey. This species in all but its 

 more pointed apex closely resembles the following Patapsco species. 

 Three other species have been described from the Atlantic Coastal Plain 

 and several are known from the Upper Cretaceous of the West, while 

 Saporta has . described a single species from the Albian of Portugal. 

 Fontaine records this genus from the Shasta flora of the Pacific coast 

 but the remains are altogether uncharacteristic. The species from the 

 Potomac Group which were formerly referred to this genus by Fontaine 

 are discussed under the genus Nelumhites in the present work. 



Menispermites potomacensis sp. nov. 

 Plate XCIII, Figs. 3, 4 

 Description. — Leaves of relatively medium or small size, orbicular 

 in 'general outline. Length 6 cm. to 9 cm. Greatest width 5 cm. to 

 8 cm. at a point about half way between the apex and the base. Margin 

 entire, more or less undulate. Apex rounded. Base rounded, ultimately 

 slightly deeurrent and possibly inclined to cordate in some specimens. 



