MARYLAND GEOLOGICAL SURVEY 825 



in an opposite or subopposite position, either from the extreme base or a 

 considerable distance above the base. In the latter case there is often a 

 prominent secondary given off from the midrib on either side below the 

 primaries. The primaries may give off a few rather long, straight, eras- 

 pedodrome secondaries to the rather full lateral margin, or they may send 

 off a stout lateral branch at varying distances above the base. Secondaries 

 from the midrib few in number, stout, irregularly spaced, craspedodrome. 

 Tertiaries transverse, platanoid. 



This species was described from the Dakota sandstone of Kansas by 

 Professor Lesquereux in 1872, who subsequently in his Cretaceous Flora 

 confused it with Platanus or Sassafras recurvatum. The latter, if it 

 really designates a species, must be restricted to the form figured by Les- 

 quereux on pi. x, fig. 3 of the Cretaceous Flora, which is decidedly differ- 

 ent from his other figures on that plate. The latter are leaves of Platanus 

 heerii, while the former must be referred to Sassafras cretaceum*or mira- 

 bile. Not only is it distinctly trilobate but the margin is entire and the 

 venation camptodrome, while in the leaves of Platanus heerii on the same 

 plate the form and margin are different and the venation is craspedo- 

 drome. Professor Heer correctly identified Platanus heerii from the 

 Atane beds of Greenland, and the forms which he figured from these beds 

 as Sassafras recurvatum are distinct from Platanus heerii and resemble 

 Lesquereux's fig. 3 mentioned above. The writer some years ago (1902, 

 loc. cit.) in discussing Sassafras recurvatum pointed out the composite 

 nature of this form and suggested that those forms which are here 

 referred to Platanus heerii were referable to Platanus, while the other 

 type was comparable with Sassafras cretaceum or mirabile. 



Professor Ward in 1887 * after sending figures of some leaves which he 

 had collected at Black Buttes, Wyoming (a probably basal Eocene 

 locality) to Lesquereux, who insisted that they were not Platanus heerii, 

 persisted in identifying them as this species, although they are obviously 

 not closely related to it. 



1 Ward, Bull. U. S. Geol. Survey, No. 37, 1887, p. 34, pi. xv, figs. 3, 4. 



