588 STEATIGRAPHICAL GEOLOGY 



B. LIFE OF THE PERIOD 



Plants. The flora of the Pliocene is transitional between the 

 luxuriant, more or less, evergreen vegetation of the Miocene period 

 and the temperate flora of modern Europe. In Southern Europe 

 the plant-assemblage was similar to that of (Eninghen, but without 

 palms or cactuses. Later plant -beds give evidence of a gradual 

 refrigeration of the climate, and toward the close of the period, if 

 we may judge from the plants of the Cromer Beds, the climate of 

 Northern Europe cannot have been very different from that of the 

 present day. 



Fauna. Of the Invertebrata the majority of the species are 

 either identical with, or merely varieties of, species now living, 

 and the proportion of extinct species gradually diminishes from a 

 percentage of 36 to 40 in the lowest beds to one of 10 or 11 in 

 the highest beds. Very few of the fossils belong to extinct genera, 

 but Congeria may be mentioned as a genus of Dreissensiidse which 

 is not now living. 



Among the Vertebrata, however, many in the Lower Pliocene 

 belong to extinct genera, and the majority of the species even in 

 the higher stages are extinct. With the advent of the Pontian 

 epoch and its southern land-connections with Africa and Asia, a 

 new mammalian fauna invaded the plains of Europe. This 

 included large herds of antelopes and gazelles, varying in size 

 and form, and for the most part allied to those of Africa. 

 With these was an animal of intermediate form between the giraffe 

 and antelopes (Helladotherium), allied to the short -necked giraffe 

 or okapi recently discovered in Africa. Herds of small wild asses 

 (Hipparion), intermediate in structure between Anchitherium and 

 the horse, also appeared in great numbers. Numerous carnivores 

 followed and preyed on the herbivorous animals, large cats and 

 panthers, including Machcerodus (a tiger), Hycena, Ictitherium 

 (allied to the civet cats), Hycenictis (combining characters of cats 

 and hyaenas), and several species of true cats (Felis). The higher 

 Pliocene is distinguished by the appearance of elephants (Elephas), 

 oxen (Bovidce), true horses (Equus), bears (Ursus), and wolves (Ganis 

 lupus), and by the abundance of deer (Gervidce). 



In France and Italy the Pliocene deposits are characterised by 

 Mastodon (Tetralophodori) arvernensis, Rhinoceros (Diceros) mega- 

 rhinus, R. (Gwlodonta) etruscus, Elephas meridionalis, Hippopotamus 

 major, Gapreolus cusanus, Elaphus perrieri, Axis pardinensis, with 

 Machairodus cultridens, Hycena striata, bears, and wolves. 



The following are some of the marine fossils which are charac- 

 teristic of the several divisions of the Pliocene Series, but as the 



