312 



THE AGE OF MAMMALS 



Casino (Tuscany) (Fig. 151, 3) which are correlated by Doperet^ with the 

 lacustrine deposits of Autrey (2) in the valley of the Saone, France. On 

 the east coast of England is a marine formation, the Coralline Crag of Suf- 

 folk (1), containing mastodon and a rhinoceros {Dicerorhinus) . This may 



Fig. 152.- 



•Europe in Lower Pliocene or Plaisancian times. White = land. 

 Dotted areas = lagoons. After de Lapparent, 1906. . 



Ruled = sea. 



not, however, represent the very base of the Pliocene. At this time south- 

 eastern England was connected with France and Belgium by an isthmus, 

 which accounts for the migrations of such continental forms as are recorded 

 in late Pliocene or early Pleistocene stages in Great Britain. - 



Transition zone. — The lignites of Casino are intercalated in marine 

 (Congeria) beds, which form the extreme base of the Pliocene below the 

 'Marnes Bleues' of the Plaisancian, so that some Italian geologists regard 

 them as part of the Upper Miocene (Pontian). The mammals of Casino, 

 while mixed, show on the whole a closer affinity to the Lower Pliocene than 

 to the Upper Miocene. Among the surviving Upper Miocene forms is the 

 tapir, Tapiriis priscus, known also from Eppelsheim. We find Sus eryman- 

 thius, a boar which occurs likewise at Pikermi; also Ictitherium, the hysena 

 stage of Pikermi. Some of these mammals when more closely studied may, 

 however, reveal a closer kinship to the characteristic Lower Pliocene species 

 such as Tapirus arvernensis, Sus provincialis, and Hipparion crassum. The 

 true Pliocene forms of Casino are the monkey (Semnopithecus monspessu- 

 lanus), an oryx {Palceoryx cordieri), a roe deer (Capreolus australis), and 



1 Deperet, Succession stratigraphique des Faunes de Mammifdres Pliocenes de I'Europe, 

 1893, p. 539. 



2 De Lapparent, Trait6 de Geologic, 1906, p. 1637. 



