244 UNITED STATES GEOLOGICAL SURVEY— TERTIARY FLORA. 



areolation is obsolete. The upper Ititeral veins join the iniihile nerve just 

 uiicler the short acumen. The leaf is of medium size, seven "centimeters 

 long and nearly four and a half wide. 



Habitat. — IMount Brosse, Colorado {Dr. F. V. Hai/den). 



Cor II us Studeri!, Heer. 



Plate XLII, Figs. 4, 5. 



ComuK Sluderi, Heer, Fl. Tert. Helv., iii, p. 27, pi. cv, figs. 18-21.— Lesqx., Annual Report, 1871, p. 293; 

 1873, p. 402. 



Leaves generally of large size, oval-lanceolate, taper-pointed or acuminate, rounded in narrowing 

 to tbe petiole ; lateral veins simple or sparingly ramified near the borders, and following them in simple 

 bows; Bbrillffi distinct, close, in right angle to the nerves, or diverging upward. 



From Heel's species, these leaves differ by their still larger size ; for, 

 though we have in the collection of the Survey some specimens with frag- 

 ments of smaller leaves, they are generally larger than those figured from the 

 European Miocene. They differ also by the branching of the nerves quite 

 near the borders, a character rarely seen in leaves of Cornus, and not at all 

 marked in Heer's species. By the size and the nervation, the American form 

 has a more marked relation to C. platyphylla, Sap. (Foss. Fl. de S^z., p. 103, 

 pi. xi, figs. 8 and 9), which merely differs by more broadly ovate leaves. The 

 affinity is marked also in the great difference of the size of these leaves ; for, 

 from the two which are figured, one is as large as our fig. 5, the other only 

 five and a half centimeters long and scarcely two broad. The smallest 

 specimen observed of the American form is six and a half centimeters long. 

 There is also a marked affinity of these leaves to that described as Artocar- 

 jmides conocepkaloidea. Sap.? in the same work (p. 356, jil. vi, fig. 6), which has 

 the lateral nerves still more distinctly branched than those figured on our 

 plate. But in these, the upper more distant nerves, evidently tending to the 

 point and aerodrome, as seen in fig. 4, are of the Cornus type. 



Habitat. — Evanston, Wyoming. Not rare at Golden, Colorado. 



€orniis r Ii a m n i Tolia , O. VTeb. 



Plate XLII, Fig. 6. 



Cornus rhamnifulia, O. Web., Paloeont., Separ.-Abdr., p. 78, pi. iv, fig. 8. — Heer, Fl. Tert. Helv., iii, p. 28, 

 pi. cv, figs. 22-25; Mioc. Bait. Fl., p. 41, pi. viii, fig. 4. — Lcsqx., Supplement to Annual Re- 

 port, 1871, p. 9. 



Leaf very entire, oval, narrowing up to a short acumen and downward to the petiole; midrib 

 straight ; lateral nerves open ; nervilles in right angle to the veins. 



This leaf seems to differ from the European species when compared to 

 those figured by Heer (loc. cit.); for these are broader, with more numerous, 



