336 UNITED STATES GEOLOGICAL SURVEY— TERTIARY FLORA. 



j)can Miocene species, Arundo Gapperti, Qkcicus Haydingeri, Fopidus Zad- 

 dachi, Ficits ?milti?iervis, and, as related types of the same age peculiar to 

 this group, \vc have Equisetum Wyomingense, Arundo rcperta, Ficus arenncea, 

 and Eucalyptus Americana, plants whose affinity seems with more recent 

 vegetable types than lliosc of the Miocene. Two species of Myrica, M. 

 nigricans and M. Bolanderi, are related to congeners of tlie upper divisions, 

 %\bile Ilex affinis, and Ampelopds terUaria, which is closely related to, even 

 perhaps identical with the \\\\ug A. quinqia/foUa, relate this group to the pres- 

 ent flora. Its affinities are evidently with less ancient types tlian those of 

 the third group. 



But still the Upper Green River division seems to have a more recent 

 character. With the first group, it has in common only Sequoia Langsdorffil, 

 Acorus brachyslachys, and a Podogonium, all Upper Miocene. Juglans ther- 

 maliit, found in lava deposits, is of doubtful reference for the station. With 

 the second, it has Taxodium distichuin , Acorus hrachysfac/iys, Alnus Kcfersteinii, 

 and Acer trilobatum, all species not merely Miocene, but, as seen from our 

 table, of a very wide and general distribution ; and, in(le[)endently of its rela- 

 tion to the other divisions, the flora of this group has Glyptostrohus Europeus, 

 P/nu.s palceostrohus, Myrica acuminata, M. undulafa, M. Ludwigii, Al.laiiloha, 

 Carpinus grandis, Fergus feronia', Quercus drymeja, Castanea intermedia, Salix 

 elongata, Popidus Ricliardsoni, Planera TJngeri, Ficus Jynx, Fraxinus jrradicta, 

 Vaccinium rtticulatmn, -dW of the European Upper Miocene; and, as closely 

 allied to plants of the same age by their types, two species of Salvinia, Se- 

 quoia angustifolia and Pterocarya Americana. The Pliocene flora of California, 

 known now by the species of the Gold-bearing Gravel of Nevada County, 

 and of some other localities, especially of Oregon, offers us also a point of 

 comparison by two identical species, Ulmus icnunieyvi,v and Acer (equidenta- 

 /M»i, while with plants of the present time the relation is marked hy Hypnum 

 Haydenii, Equisetum limosum, and the fine Staphylea acuminata. All this 

 evidently weakens in fiiis flora the Miocene facies, so distinct in that of the 

 third group. Indeed, taken altogether, both divisions of the fourth group 

 nfight be ascribed to the Lower Pliocene; four of their species being, as far 

 as it can be ascertained from the characters of the leaves, identical with plants 

 of our time. The relation to tlu; European i\Iiocene is, however, still too 

 close, while it is too distant from the Pliocene flora represented l)y the s[)e- 

 cics of the Gold Gravel of California. 



