KNowLToN.] DESCRIPTION OF SPECIES. 41 



a very short obtusoh'afuminate apex; maroMii rather coarsely toothed, 

 most of the teeth, but especially those on the lower half of the blade, 

 with several smaller teeth; midrib rather thick, straight; secondaries 

 about 9 pairs, opposite below, becoming subopposite above, the two 

 lower pairs emerging at an angle of a])out 20", others about 45°, all 

 craspedodrome and ending in the large teeth, often with one or two 

 branches on the lower side, which pass to smaller teeth; nervilles thin, 

 mainly percurrent and oblique to the secondaries; tiner nervation pro- 

 ducing a minute network, 



I have ventured to describe this species on the single example 

 figured. It is a little more than 4.5 cm. in length and is 4 cm. in width. 

 As may be seen, it is a very perfect and symmetrical leaf, n(>arly cir- 

 cular in outline, with rather coarseh', dou))ly dentate margins. 



Among living forms this is perhaps closest to Betxda occidentalis 

 Hooker, which is now found in the same general region. It has the 

 same shape and nervation, but differs slightl}^ in the marginal denta- 

 tion. It is also quite similar, except as regards the margin, to certain 

 forms of B. jx/pijr/fera Marshall. 



Among fossil forms it has a number of evident affinities. From 

 B. heteroiiiorpha it differs in being nearly circular in shape, with an 

 equal base and regularly spaced secondaries. 



Locality. — Bridge Creek, Oregon. Collected b}^ Maj. Charles E. 

 Bendire (U. S. Nat. Mus., No. 8485). 



Betula angustifolia Newb. 



Betcla AXtiUSTiFoi.iA Newl)., Proc. U. S. Nat. Mus., Vol. V, p. 508; Later Extinct 

 Floras, p. 63, PI. XLVI, tig. 5; V\. XLVII, fig. 5, 1898. 



A large number of leaves of this species are present in every col- 

 lection from this locality. 



Locality. — Bridge Creek, Oregon. Collected l)y Rev. Thomas Con- 

 don (Types, U. S. Nat. Mus., Nos. 7074, 7075). 



Betula? uayana, n. sp. 



PI. IV, fig. 4. 



Leaf small, membranaceous, ovate-cordate, obtuse at apex; margin 

 very coarsely toothed; midrib thin; secondaries thm and obscure, 

 about four pairs, alternate, ending in the larger teeth; finer nervation 

 producing a very fine network. 



A single leaf only. The length is 2 cm. and the width 1.5 cul 

 Locality. — Mascall beds, Van Horn's ranch, Oregon, about 12 miles 

 west of Mount Vernon, Grant County, Oregon, Collected by Knowl- 

 ton and Merriam, July, 1901 (U. S. Nat. Mus., No. 8535). 



