20 GEOLOGICAL SURVEY OF THE TERRITORIES. 



it proves at least tbat ours is truly indigenous. The similarity of the 

 fossil leaves with those of the living sx^ecies confirms the assertion. And 

 the antiquity of race, too, may be indicated by the wide range of distri- 

 bution and general prevalence ofMorus rubra, from Florida to Lalie Erie. 

 ]N^o species of Morus has been as yet recognized in a fossil state. It is 

 the same with Ampelopsis, a genus still more evidently North American 

 than Morus-, for no species of ivne. Ampelopsis is known fi-om another 

 country.* The relation of form between the fossil species Ampelopsis 

 tertiaria and the living A. quinquefoUa is as distinctly marked as for the 

 two species of Motnis, and also its geographical distribution and its pre- 

 dominance in our flora. Both species are in intimate aiSnity to our 

 I'Torth American vegetation. They are seen everywhere and known 

 and liked by everybody. The one is the friend of the farmers by its 

 shade, of his children delighted by the pleasantness of its fruits ; the 

 other adorns our dwellings when allowed to grow in our gardens. And 

 when left to its own work, it covers with green foliage the dead trees 

 and the barren rocks, tempering desolation and ruin b}' hiding them 

 under elegant fringes and garlands painted of the richest colors. It is 

 worth something to know that the origin of the Virginian Creeper and of 

 the Red Mulberry is traceable to the Tertiary formations of North 

 America. 



There is still a number of genera from our arborescent flora which 

 liave not, as yet, any representatives recognized in the Tertiary — Asi- 

 rnina, for example, Aesculus, Samamelis, some Bosacecc, Ericacecc, &c. 

 The preservation and fossilization of leaves is more or less dependent 

 upon the consistence of tlieir texture, thin leaves being mostl}" destroyed 

 by maceration too soon to leave distinct traces of their forms when im- 

 bedded in clay or sand deposits. In examining, upon the ground, the 

 dead leaves of our forests in spring, the difference in the degree of pre- 

 servation resulting of texture is easily remarked. For example, upon a 

 lot occupied by Oak, Beach, Elm, and Maple trees, in nearly equal pro- 

 portion, the leaves of the three first kinds will be found lieaped every- 

 where and entire, while scarcely a few skeletons of decaying leaves of 

 Maple are distinguishable. This probably explains the absence of some 

 species, and also the disproportion of representatives of others in the 

 Tertiary; as, for example, of the species of Acer, which, already predom- 

 inant at the Cretaceous epoch, and having a large number of species in 

 the present flora of our North American continent, have been as yet 

 rarely found in our Tertiary formations. It must be said, too, that we 

 know as yet but a very small part of the vegetation of the Tertiary, and 

 that every new lot of specimens affords materials to modify suppositions 

 which might be offered on the causes of the distribution of species. In 

 the former report I alluded to the scarcity of the remains of Willows in 

 our Tertiary, in comparison with their great number in the Cretaceous. 

 In the present notes, four species of Salix, as yet unknown in our fossil 

 flora, have been described, and probably a number of others will be 

 found still. 



However, it is true that some of our ancient types have disappeared, 

 or show a tendency to disappear from our present 'flora, the tj'^pes 

 related to the present vegetation of Australia, for example, Eucalyptus 

 of the Tertiary, which will be probably found in the Cretaceous with 

 Phillocladus and Proteoides ; some others also, now marked in the flora 

 of Japan and China, which appear to have traveled westward, as Cin- 



* Ampelopsis iotria, D. C, is described from Zanzibar, Africa. As it has simple leaves 

 and fruit eatable, it is probably referable to Vitis. 



