THE MIOCENE .PERIOD. Srl 
can plants to Europe was thus permitted. This view is borne 
out by the fact that the Miocene plants of Europe are most 
nearly allied to the living plants of the eastern or Atlantic 
seaboard of the United States, and also by the occurrence of 
a rich Miocene flora in Greenland. As regards Greenland, 
Dr Heer has determined that the Miocene plants indicate a 
temperate climate in that country, with a mean annual tem- 
perature at least 30° warmer than it is at present. 
The present limit of trees is the isothermal which gives the 
mean temperature of 50° Fahr. in July, or about the parallel 
of 67° N. latitude. In Miocene times, however, the Limes, 
Cypresses, and Plane-trees reach the 79th degree of latitude, 
and the Pines and Poplars must have ranged even further 
north than this. 
The Lnvertebrate Animals of the Miocene period are very 
numerous, but they belong for the most part to existing types, 
and they can only receive scanty consideration here. The 
little shells of Foraminifera are extremely abundant in some 
beds, the genera being in many cases such as now flourish 
abundantly in our seas. The principal forms belong to the 
genera TZextularia (fig. 237), Robulina, Glandulina, Poly- 
stomella, Amphistegina, &c. 
Corals are very abundant, 
in many instances forming 
regular “‘ reefs ;” but all the 
more important groups are 
in existence at the present 
day. The Red Coral (Cor- 
allium), so largely sought 
after as an ornamental ma- 
terial, appears for the first s 
time in deposits of this age. ** "ae 
Amongst the Zchinoderms, 
we meet with Heart-Urchins (Spatangus), Cake - Urchins 
(Scutella, fig. 238), and various other forms, the majority of 
which are ciosely allied to forms now in existence. 
Numerous Crabs and Lobsters represent the Crustacea; but 
the most important of the Miocene Articulate Animals are the 
Insects. Of these, more than thirteen hundred species have 
been determined by Dr Heer from the Miocene strata of 
Switzerland alone. They include almost all the existing 
orders of insects, such as numerous and varied forms of 
Beetles (Coleoptera), Forest-bugs (Hemiptera), Ants (Hymen- 
optera), Flies (Diptera), Termites and Dragon- flies (Weurop- 
tera), Grasshoppers (Orthoprera), and Butterflies (Lepidoptera). 
