492 Systematic Paleontology 



outline and acutely (but not narrowly) pointed. Sinuses narrow and 

 rounded, the main ones extending half way to the base or somewhat less, 

 the subordinate ones extremely shallow. Texture coriaceous. Petiole" 

 stout, as is the usually curved midrib. Lateral primaries two in number, 

 stout, basal or subbasal, sending off a stout branch on the outside which 

 is camptodrome in cases where the lateral lobe is entire and running to 

 the apex of the subordinate lobe when the latter is present. True 

 secondaries numerous, not coarse, camptodrome. Base of the leaf broadly 

 cuneate or truncate, slightly decurrent. 



This species differs from the preceding in its uniformly larger size 

 and consequent coarseness of texture and venation; in its usually more 

 elongate form and less sublobation; in its truncate base and broader, 

 more acute lobes. 



As the synonymy shows, the writer has united Aralicephyllum magni- 

 folium and Aralicephyllum aceroides of Fontaine which show absolutely 

 no distinctive characters except that the material is in the one case 

 more fragmentery than in the other. With these it has been found 

 necessary to unite the genus Aceripliyllum of Fontaine founded upon 

 a single specimen (as nearly as can be made out from the U. S. National 

 Museum collection) which is identical with the remains just cited. 

 Professor Fontaine compares it with Aralicephyllum and gives as its 

 only diagnostic character the lack of subordinate lobes, which as we 

 have seen is of minor importance in the present genus. Finally 

 Hedercephyllum angulatum Fontaine is also found to be identical with 

 the foregoing. It was based upon a single incomplete specimen, the only 

 one ever discovered, and was compared by its original describer with 

 Aralicephyllum, with which it undoubtedly naturally belongs. 



The present species is less common than the preceding and, like it, 

 is thus far restricted to the vicinity of the Potomac Kiver, occurring in 

 beds of Patapsco age in both Virginia and Maryland. Because of its 

 large size it is usually found in a fragmentary condition. 



Occwrrewce.— Patapsco Fokmation. Near Brooke, 72-mile post, 

 Virginia; Stump Neck, Charles County, Maryland. 



Collection. — U. S. National Museum. 



