302 GEOLOGICAL SURVEY OF THE TEKRITOEIES. 



ter, thougli still indistinctly traced in the leaves of Castanea, and of 

 some species of chestnut-oaks, is far less regular, the upper branches 

 which follow the borders being of various sizes, not so exactly parallel 

 to the borders, and not in close proximity to them. This new species is 

 intimately related to Bryopltyllum Dewalquei Sap. & Mer. {Flor de Oe- 

 linden), especially to the fragment figured in PI. Ill, Fig. 2. It differs 

 only by the shorter, less acute teeth of the borders, the slightly falcate 

 form of the leaf, and the close thin flbrillse. 

 Habitat. — Point of Eocks, Wni. Cleburn. 



15. POPULUS MELANARTA, Hecr. 



Leaves with a long, slender petiole; deltoid, subtruncate at base; 

 borders acutely serrate ; primary basilar lateral nerves emerging from 

 above the border base of the leaf, with a pair of thin marginal veinlets 

 underneath. 



Considering what can be seen of this leaf from the fragment which 

 represents merely its lower half, with the long, slender petiole, the dis- 

 tinct nervation, and a few of the border- teeth, it exhibits characters in 

 accordance with those described above, and translated from Schimper's 

 Vegetable Paleontology, and especially with the figure given of this 

 species in Flor. Tert. Helv. (PI. LIV, fig. 7). Professor Herr remarks, 

 that it essentially differs from Populus latior, var. subtruncata, by the 

 position of the lateral primary nerves at a distance from the border-base 

 of the leaves. In the leaf figured as indicated above, this distance is 

 still greater than in that in the Flor. Helv. Heer remarks also that 

 he has seen a large number of specimens of the same species, but that 

 in all except one, which he has figured, the upper part of the leaves 

 was' destroyed, as it is in ours. He mentions as distinctive characters, 

 the acutely serrate borders of the leaves, and the middle nerve thicker 

 than the lateral ones, the same as seen upon our specimen. I have, 

 therefore, no doubt about the relation of this leaf to the European 

 species. 



Habitat. — Point of Eocks, Dr. F. V. Hayden. 



16. Populus melanarioides, sp. nov. 



Leaf subcoriaceous, nearly round, subtruncate at base, long-petioled ; 

 borders undulate ; nervation ternate from above the base of the leaf, 

 secondary veins two pairs, at a great distance from the primary ones, 

 these much branched outside ; the others simple, all the divisions pass- 

 ing to near the borders, where they become effaced in the areolation ; 

 nervilles thick, flexuous, in right angle to the veins, forming by rami- 

 fication at right angle square polygonal meshes. 



By the subcoriaceous substance, the long slender petiole of the leaves, 

 this species is referable to the section of the Trepidce (Trembling Pop- 

 lars). As in Fopulus tremulccfolia, Sap. (Et., 3, 2, p. 26, PI. Ill, fig. 4), 

 to which this species is allied, the veins and their branches pass through 

 the areas to very near the borders, which they seem to reach. The 

 American form differs merely by less-distinctly undulate borders, the 

 distance of the primary lateral nerves above the base, and by the great 

 distance of the secondary veins. These two last characters are, how- 

 ever, of no moment for the specification of poplar -leaves, as can be re- 

 marked in the examination of a few leaves of the too common Fopulus 

 alba. In fossil species, Fopulus Massiliensis^ Sap. (Et., 3, 2, p. 30, PI. II, 

 fig. 6), is represented by three leaves, eacli of a different character of 

 nervation. The relation of this species with that of the Tertiary 



