DESCRIPTIONS OF SPEC IKS. 63 



upper Missouri will doubtless supply a larger amount of material illustrat- 

 ing this species, and may prove it to be worthy of recognition as distinct 

 from all others. Taken by itself it presents such striking differences from 

 the other species of Corylus known that it has seemed to me best to give it 

 a distinct name. 



Formation and locality: Tertiary (Fort Union group). Fort Union, 

 Dakota, 



Corylus rostrata fossilis Newb. 



PI. XXXII, figs. 1-3. 



Corylus rostrata Ait. Newb. Ann. N. Y. Lye. Nat. Hist., Vol. IX (April, 1868), 

 p. 60; Ills. Cret. and Tert. PI. (187S), PI. XV, figs. 1-3. 



"These leaves offer no characters by which they can be distinguished 

 from those of the living 'beaked hazel-nut,' They are clearly those of a 

 hazel, and show such a perfect correspondence with those of one of the 

 species living in the region where these fossils occur that, until the fruit 

 shall be found and the question definitely settled, I have thought it best to 

 consider them as identical." 



Collected by Dr. F. V. Hayden. 



•Corylus insignis Heer (Fl. Tert, Helv., Vol. II, p. 43. PI. LXXIII, 

 figs. 11-17; Fl. Foss. Arct., Vol. II, Abth. IV, p. 469, PI. XLIX, fig. 5) is 

 closely allied to the plant under consideration, and should perhaps be united 

 with it. 



Formation and locality: Tertiary (Fort Union group). Fort Union, 

 Dakota. 



Betula angustifolia Newb. 



PI. XL VI, fig. 5; XLVII, fig. 5. 

 Proc. U. S. Nat. Mus., Vol. V (March 21, 1883), p. 508. 



"Leaves petioled, oblong-lanceolate, 3 inches long by 1 inch wide; 

 wedge-shaped or slightly rounded at the base, acuminate at summit; mar- 

 gins finely serrate below, coarsely and doubly serrate above; nerves slen- 

 der, about eight branches on each side of the midrib." 



These leaves, of which there are a number in the collection made by 

 Rev. Thomas Condon, are distinguished from the other species of Betula 

 with which they are associated by their narrower and more elongated form 



