DESCRIPTIONS OF SPECIES. 59 



PI. XXXIV, fig. 2) is apparently much more strongly nerved. The gen- 

 eral form was perhaps similar, although Dunker's specimen wants both 

 point and base. 



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

 Nebraska. 



Salix membranacea Newb. 



PI. II, figs. 5-8, i Sa. 



Aim. N. Y. Lye. Nat. Hist., Vol. IX (April, 1868), p. 19; Ills. Cret. and Tert. 

 PL (1878), PI. I, figs. 5-8a [fig. 8a not named on plate]. 



"Leaves petioled, large, smooth, and thin, lanceolate, long-pointed, 

 rounded or abruptly narrowed at the base, near which they are broadest; 

 margins entire; medial nerve slender, often curved, secondary nerves 

 remote, very regularly and uniformly arched 'from their bases, terminating 

 in or produced along the margins till they anastomose; tertiary nerves 

 given off nearly at right angles, forming a very uniform network of which 

 the areoles are polygonal and often quadrate." 



This is a strongly marked species, collected by Prof. George H. Cook, 

 of which I have specimens fossilized in fine clay and exhibiting with great 

 distinctness all the details of nervation. It was evidently thin and mem- 

 branous in texture, though attaining a large size. Like most of the 

 willows, it is frequently unsymmetrical, one side being most developed and 

 the midrib curved. 



The leaf is broadest near the base, and is thence narrowed into a long 

 and acute point. 



Formation and locality: Cretaceous (Raritan). Amboy Clays, Raritan 

 River, New Jersey. 



Order BETULACEjE. 



Carpinus grandis Ung. 

 PI. LIV, fig. 3, in part ; LV, fig. 6. 

 Synop. Foss. PI. (1845), p. 220. 



Leaves which seemed to represent this very widespread species of 

 Carpinus were collected by Professor Dana at Birch Bay, near the mouth 



1 This specimen may also be found figured in Flora of the Amboy Clays, PL XXIX, fig. 12. 

 (Mon. U. S. Geol. Surv., Vol. XXVI.)— A. H. 



