412 GEOLOGICAL SUEVEY OF THE TEEEITOKIES. 



MiRiCA UNDULATA, Hecr. 



Leaf membranaceous or subcoriaceous, small, 3J centimeters long, (tlie 

 point and base are destroyed.) 1 centimeter broad, linear-oblong, with 

 deeply-undulate borders ; nervation camptodrome ; lateral veins open, 

 joined by curved fibrillse nearly in right angle to the veins, forming by 

 ramification a small polygonal areolation ; the direction of the second- 

 ary veins intermixed with shorter tertiary ones, their mode of curving 

 to and along the borders, and the areolation, are of the same kind as in 

 the leaves of Myraca (Diandra) undulata, lleer, (Fl. Tert. Helv., Ill, 

 p. 188, PL cliii. Figs. 22, 23.) The American leaf is in its size and 

 its tapering base exactly similar to Fig. 23 j its undulations are only 

 more definite. I consider it as identical. 



Hahitat. — Elko, Prof. Cope. 



Myrica latiloba, Heer, var. Acutiloba. 



Leaves membranaceous, linear-lanceolate or oblong-lanceolate, pin- 

 nately deeply divided in large, pointed, triangular lobes, narrowed to a 

 short petiole ; secondary veins distinct, craspedodrome, open, ascend- 

 ing to the point of the lobes ; tertiary veins under the same degree of 

 divergence, curving along the borders, and anastomosing with pinnate 

 branches of the secondary ones. This species is represented by one 

 fragment only, showing the lower part of a leaf, bearing three lobes 

 on one side and only one on the other. In Heer's species, (Fl. Tert. 

 Helv., Ill, p. 176, PI. cl, Figs. 12-15,) the leaflets are more obtuse or 

 less pointed than in the American leaf, which also differs by a somewhat 

 longer petiole. This form is apparently a mere variety. 



Habitat. — Middle Park, Colorado, Dr. Hayden. 



Myrica partita, sp. nov. 



Leaf subcoriaceous, linear, narrow, one centimeter broad, alternately 

 equally lobate ; lobes distinct to the base, turned upward, broadly lan- 

 ceolate, narrowed to a short point, denticulate along the lower side and 

 near the point of the upper border j secondary vein ascending to the 

 point of the acumen ; tertiary veins parallel, shorter, passing up to the 

 lower teeth in anastomosing by nervilles in right angle to the second- 

 ary vein ; areolation round- i)olygonal, small. Like the former, the spe- 

 cies is represented by a fragment only. It is distantly related to the 

 following. 



Hahitat. — Elko, Nevada, Frof. Cope. 



Myrica (Comptonia) Brongnarti(?), Ett. 



Leaf coriaceous, linear, narrow, half a centimeter broad, alternately 

 pinnately obtusely dentate; nervation obsolete, pinnate, camptodrome; 

 secondary veins simple. It is not possible to positively recognize the 

 nervation of this leaf, which, by undulation of its surface correspond- 

 ing with the teeth, has the fades of a small branch of conifer. It re- 

 sembles some of the leaves published in Ett. (Haring Flor.) as Diandra 

 Brongnarti., especially that of PI. xix. Fig. 20 ; the lobes, however, being 

 less deeply parted, or like mere obtuse teeth, though the appearance is 

 that of a lobate leaf. 



Habitat. — Elko, Prof. Cope. 



Ulmus tenuinervis, sp. nov. 



Leaves thin, very unequal at the base, deeply cordate on one side, 

 tapering on the other to the middle nerve, half a centimeter higher up ; 



