GEOLOGICAL SUEVEY OF THE TEEEITORIES. 311 



ties. But it is remarkable tliat the same predominance is continued in 

 our present flora, as we have, in counting the marked varieties, twice as 

 many species of poplars as are found in Europe under the same latitude. 

 The willows show in their distribution the same analogy, but in a con- 

 trary way. As yet we know only four species of Salix from our Tertiary 

 measures, while Europe has thirteen. And this difference is the more 

 remarkable that we have in our Cretaceous already five species of 

 this genus. But, in considering our present flora, we find for Europe 

 thirty-four species of willows, while we count only twenty-one for North 

 America — six of them at least introduced from Europe. Of oaks, Europe 

 has thirty-five Tertiary species on nine hundred and twenty species of 

 plants known from this formation, or about one twenty -fifth, while this 

 genus as yet represents one-tenth of our Tertiary species. Therefore, here 

 also we see the preponderance of this genus in our actual flora indicated 

 already in the Tertiary. The same can be said for Platanus, Magnolia, 

 Bhamnus, and Juglans. Most of the genera, about equally represented 

 in Europe and in America, and of which no living species are found now 

 in the flora of the old continent, have still representatives with us ; as, 

 for example, Sequoia, Sahal, Liqttidambar, Ficus, Latirus, Sassafras, Lirio- 

 dendron. Magnolia, Negundo, Carya, &c. Of genera represented in the 

 North American Tertiary and not in the European Miocene, like Celtis, 

 we have still living species also. On the other side, of some genera or 

 orders which had a marked number of species in the Tertiary of Europe 

 and none in ours, like the Daphnoides, the FroteaceWj the Myrsinem, 

 none appears in our present flora. 



The same comparison pursued in a contrary direction, or in regard 

 to difference in latitude, indicates a relation of our Tertiary flora with 

 that of the Arctic regions.* Eive of our species marked as of a wide 

 distribution — one #erw, three Conifers, one Fhragniites, one Acorns — ha;ve 

 identical representatives in Greenland and Spitzbergen, Of species of a 

 lesser range, we have in both PopuVus arctica, P. Zaddachi, Alnus 

 Kefersteinii, Quercus Lyellii, Q.Drymeja, Q. LaJiarpi, Gorylus McQuarryi, 

 Fagus Beucalionis, Platanus Ouillelmce, P. aceroides, one species of 

 Liriodendron, one of Magnolia, Paliurus Colomhi, five species of Juglans, 

 (perhaps reducible to two,) about one-eighth of our whole Tertiary flora, 

 or twenty-four species, eleven of which are also in the same formation of 

 Europe. With the Alaska Tertiary flora, of which only fifty-six species 

 are known, we have eighteen identical species, ten of which are also in 

 the Miocene of Europe ; and with the Baltic flora, fourteen, two of 

 which only, Populus ZaddacM and Andromeda reticulata, are not marked 

 in Heers Fl. Ter. Helv. These data are scanty, indeed; but they 

 indicate already between our North American Tertiary flora and that 

 of the arctic regions an intimate, relation, considering the difference of 

 latitude, closer, indeed, (one-fifteenth,) than with the European Tertiary, 

 (ond twenty- sixth.) At the same time, the evidence is against a more 

 marked analogy than could be surmised from the difference of latitude; 

 for in comparing the types of both groups of fossil plants of the arctic 

 and of the North American Tertiary, the northern and southern facies 

 are distinctly recognized. The arctic flora, including Alaska, has no 

 Cinnamomum. These so wide-spread representatives of a warmer climate 

 in the Tertiary are first seen in Vancouver and in our North American 

 Tertiary, as far up as Fort Union, near the 48'^ of latitude. It has also 

 no Sabal, while immense and numerous leaves of this species character- 



* Tho comparison is made from the species enumerated in the table, including those 

 of Mississippi, with the Arctic Tertiary Flora of Heer, which describes the Tertiary- 

 plants of Greenland, Spitzbergen, Mackenzie, and Iceland. 



