LOWER EOCENE, ENGLAND. 
263 
black carbonaceous seams and lignite. In the midst of these 
leaf-beds in Studland Bay, Purbeck shells of the genus Uiiio 
attest the fresh-water origin of the white clay. 
No less than forty species of plants are mentioned by MM. 
de la Harpe and Gaudin from this formation in Hampshire, 
among which the Proteacese {Dryandra^ etc.) and the hg 
tribe are abundant, as well as the cinnamon and several oth¬ 
er laurinese, with some papilionaceous plants. On the whole, 
they remind the botanist of the types of subtropical India 
and Australia.^ 
Heer has mentioned several species which are common to 
this Alum Bay flora and that of Monte Bolca, near Verona, 
so celebrated for its fossil fish, and where the strata contain 
nummulites and other Middle Eocene fossils. He has par¬ 
ticularly alluded to Aralia primigenia (of which genus a 
fruit has since been found by Mr. Mitchell at Bournemouth), 
Daphnogene Veronensis^ and Ficus granadilla^ as among the 
species common to and characteristic of the Isle of Wight 
and Italian Eocene beds; and he observes that in the flora 
of this period those forms of a temperate climate which con¬ 
stitute a marked feature in the European Miocene forma¬ 
tions, such as the willow, poplar, birch, alder, elm, hornbeam, 
oak, fir, and pine, are wanting. The American types are also 
absent, or much more feebly represented than in the Mio¬ 
cene period, although fine specimens of the fan-palm {Sahal) 
have been found in these Eocene clays at Studland. The 
number of exotic forms which are common to the Eocene 
and Miocene strata of Europe, like those to be alluded to in 
the sequel which are common to the Eocene and Cretaceous 
fauna, demonstrate the remoteness of the times in which the 
geographical distribution of living plants originated. A 
great majority of the Eocene genera have disappeared from 
our temperate climates, but not the whole of them ; and they 
must all have exerted some influence on the assemblages of 
species which succeeded them. Many of these last occur¬ 
ring in the Upper Miocene are indeed so closely allied to 
the flora now surviving as to make it questionable, even in 
the opinion of naturalists opposed to the doctrine of trans¬ 
mutation, whether thev are not genealogically related the 
one to the other. 
LOWER EOCENE FORMATIONS, ENGLAND. 
London Clay (C. 1, Table, p. 252). —This formation under¬ 
lies the-preceding, and sometimes attains a thickness of 500. 
feet. It consists of tenacious brown and bluish-gray clay, 
* Heer, Climat et Ye'getation du Pays Tertiaire, p. 172. 
