160 UNITED STATES GEOLOGICAL SURVEY— TERTIARY FLOKa. 



Que re IIS pi at a III a, Heer. 

 Plato XXI, Fig. 1. 



Quercua platania, Heer, Fl. Foss. Arct., i, p. 109, pi. xi, fig. 6, xlvi, fig. 7; ii, pi. xlvi, fig. 5, Iv, fig. 3 c; 

 Spitz. Fl., p. 57, pi. xii, figs. 5-7.— Lesqx., Annual Keport, 1872, p. 386. 



Leaves membranaceous, very large, round-cordate to tbo base ; borders simply dentate ; secondary 

 veins thick, the basilar ones opposite, more distant from the upper pairs, and branching, all slightly 

 curving inside in ascending to the borders, craspedodrome. 



This fine leaf indicates, by the preserved fragment, its lower part, a 

 width of thirteen centimeters and a length of about twenty centimeters with- 

 out the petiole. It is rounded, auricled, or deeply cordate at the base, with 

 the borders unequally but simply dentate, the short, outside-turned teeth 

 varying in distance, following the relative position of the secondary veins and 

 of their branches, which all enter them. The lateral veins are thick, the 

 lower ones opposite and somewhat more distant from the first pair of veins 

 above, as these are from the following ones in ascending. Comparing our 

 figure with that of Heer {loc. cit., pi. xlvi, fig. 5), the remarkable affinity of 

 tliose leaves appears striking. Their size, their form, and their nervation are the 

 same. They merely differ in the character of the teeth, which, pointed along 

 the borders of the American leaf, are obtuse and rhore prominent, in that of 

 Greenland. But this difference is negatived by Prof Heer, who, in his 

 description of the specimens from Spitzbergen, which he refers to this species, 

 and which have the borders of the leaves cut in short, acute teeth, remarks 

 (p. 57, loc. cit) that the smaller teeth cannot separate this form from that of 

 Greenland. The locality, Carbon, where a number of Arctic and Alaskan 

 species have been found, renders more probable the specific relation of this 

 leaf to those described under this name from Greenland. We have the same 

 kind also from the Miocene of Roach Hill, Oregon. 



Considering its relation, our leaf as fiir as it is known, has the same 

 degree of affinity to Viburnum platanoides, Lesqx. (pi. xxxviii, fig. 8), as the 

 former described leaves of Quercus Viburnifolia have with V. marginatum; 

 supposing, however, that the upper destroyed part of the specimen is rounded 

 or abruptly pointed, as the direction and the thinning of the upper secondary 

 nerves seem to indicate, and not lengthened and lanceolate, as it is in fig. G 

 of pi. xi of Heer (loc. cit.). 



Habitat. — Carbon, Wyoming, with Populus Arctica, Paliurus, Colomhi, etc. 



