102 THE LATER EXTINCT FLORAS OF NORTH AMERICA. 



page 93, and in his Cretaceous Flora, page 56, where it is illustrated 

 by numerous figures. Nearly all of these represent somewhat deeply five- 

 lobed leaves, of which the lobes are pointed and sometimes acute. The 

 figure given on PI. XII of this monograph shows that the lobes may some- 

 times become broadly rounded. , 



Since this note was written I have found in the Amboy Clays of 

 New Jersey — a formation about on a level geologically with the Dakota 

 group — leaves which I can not distinguish from those figured by Mr. 

 Lesquereux. 1 All these five-lobed entire margined leaves contrast some- 

 what strongly with those of the living species, and I am disposed to 

 doubt the propriety of referring them to the same genus. The leaves of 

 L. styraciflua are quite variable in size and form, but always have pointed 

 lobes and serrated margins. In Northern Mexico all the "sweet gum" 

 trees have three-lobed leaves, rarely more than 3 inches in diameter, 

 while in New Jersey the leaves are from five to seven lobed and gen- 

 erally from 5 to 6 inches in diameter. 



In the Puget Sound group a small three-lobed leaf occurs which could 

 hardly be distinguished from these of the Mexican variety of the common 

 species. These, like those of L. Europceus, as figured by Unger and Heer, 

 can not be doubted to be Liquidambar, but the leaves now under consider- 

 ation seem to me more likely to belong to the group of three- to five-lobed 

 Aralias that are so common in the Dakota and Amboy groups. 



Formation and locality: Cretaceous (Dakota group). Blackbird Hill, 

 Nebraska, and Fort Harker, Kansas. 



Order PLATANACE^. 

 Platanus aspera Newb. 

 PL XLII, figs. 1-3; XLIV, fig. 5; LIX, fig. 3. 

 Proc. U. S. Nat. Mus., Vol. V (March 21, 1883), p. 509. 



"Leaves attaining a diameter of 1 foot or more; petioled; rounded at 

 the base, more or less three-lobed, sometimes nearly ovoid; nervation 

 strong, about nine branches on each side of the midrib; margins deeply, 

 and often compoundly toothed." 



Collected by Rev. Thomas Condon. 



1 Dr. Newberry probably has reference to Aralia rotundiloba Newb. Flora of the Amboy 

 Clays, p. 118, PI. XXVIIL fig. 5; XXXVI, fig. 9 (Mon. U. S. Geol. Surv., Vol. XXVI).— A. H. 



