290 HISTORICAL PALAZAONTOLOGY. 
tinued, and still further enforced. The Cycads of the Secondary 
period, if they have not totally disappeared, are exceedingly 
rare; and the Conifers, losing the predominance which they 
enjoyed in the Mesozoic, are now relegated to a subordinate 
though well-defined place in the terrestrial vegetation. ‘The 
great majority of the Eocene plants are referable to the groups 
of the Angiospermous Exogens and the Monocotyledons ; and 
the vegetation of the period, upon the whole, approximates 
closely to that now existing upon the earth. ‘The plants of the 
European Eocene are, however, in the main most closely allied 
to forms which are now characteristic of tropical or sub-tropical 
regions. ‘Thus, in the London Clay are found numerous fruits 
of Palms (Vifadites, fig. 213), along with various other plants, 
most of which indicate a warm climate 
as prevailing in the south of England 
at the commencement of the Eocene 
period. In the Eocene strata of North 
America occur numerous plants belong- 
ing to existing types—such as Palms, 
Conifers, the Magnolia, Cinnamon, Fig, 
Dog-wood, Maple,. Hickory, Poplar, 
Plane, &c. -Taken as ay wholewieee 
Eocene flora of North America is nearly 
related to that of the Miocene strata of 
Europe, as well as to that now existing 
p Big 21a Nitadites 22- «in: the American area. ) We mayeega 
London Clay, Isle es clude, therefore, that “the forests of 
the American Eocene resembled those 
of the European Miocene, and even of modern America” 
(Dana). 
As regards the auzmals of the Eocene period, the Protosoans 
are represented by numerous /oramzinifera, which reach here 
their maximum of development, both as regards the size of 
individuals and the number of generic types. Many of the 
Eocene Foraminifers are of small size; but even these not 
uncommonly form whole rock-masses. ‘Thus, the so-called 
“Miliolte Limestone” of the Paris basin, largely used as a 
building-stone, is almost wholly composed of the shells of a 
small species of Miliola. ‘The most remarkable, however, of 
the many members of this group of animals which flourished in 
Eocene times, are the “ Nummulites ” (Vwmmulina), so called 
from their resemblance in shape to coins (Lat. zawmmus, a coin). 
The Nummulites are amongst the largest of all known /ora- 
minifera, sometimes attaining a size of three inches in circum- 
ference ; and their internal structure is very complex (fig. 214). 
