119 



ever, are so similar that they were formerly considered by botanists as mere 

 varieties, and are still admitted as such by some. They have on both 

 continents the same wide and general distribution, being essential constituents 

 of the forests of our present time. Per contra, most of the species described 

 as yet from the Tertiary more or less widely differ from the European or the 

 North American types. F. pristina is distantly related to our F. ferruginea. 

 F. antipoji, from the Miocene of Alaska, is related to the same by the slightly 

 dentate borders, but differs, indeed, by the larger size of the more taper- 

 pointed leaves. F. macrophytta, of the same formation and country, has the 

 leaves entire, like the European species, but still of a tar larger size, the spec- 

 imen figured by Heer representing a leaf sixteen to eighteen centimeters long 

 and ten centimeters wide. F. deucalionis, F. feronice, and F. horrida have 

 borders of leaves more or less dentate, and therefore more like the North 

 American type. The beech has now representatives in far distant coun- 

 tries, but its types are local, and all the exotic ones differ from that of our 

 fossil species. Japan has one species, with leaves cordate at base and bor- 

 ders obtusely crenate, the secondary nerves tending to the sinuses. Chili has 

 five, with leaves obtuse, truncate at the base, and borders mostly doubly 

 serrate. South Central America has one of very wide distribution ; 

 it has small, coriaceous dentate leaves. New Zealand has four, all with 

 doubly serrate leaves, and the lower surface white, tomentose; and Tasmania 

 has for its share two species of a still more distant type, with obtuse, trun- 

 cate, and dentate leaves. It is only when out of the geographical limits of 

 the north occidental flora or in the Grecian Archipelago that we find a fossil 

 species of Fagus related to an exotic form with doubly dentate small leaves, 

 F. dentata, from Eubea, a species which Unger compares to the Chilian F. 

 obliqua. 



After this we find described, from our Cretaceous flora, Betula beatriciana, 

 comparable, by the form of its leaves and its nervation, to our B. nigra, 

 widely distributed from the northern shores of Lake Superior to Florida ; 

 leaves and seeds of Myrica; at least these which we bave figured under this 

 name are undistinguishablc from Heer's seeds of Myrica, described from the 

 Cretaceous flora of Quedlinburg, but, indeed, more flattened than the seeds of 

 any of our present species ; then two leaves which Saporta considers as rep- 

 resentatives of the genus Celtis, of which we have still two species in our flora; 

 then leaves of oaks, Qucrcus primordialis, of the type of the so widely distrib- 



