184 



THE AGE OF MAMMALS 



lagoons and swamps, with lignitic deposits. The flora indicates an increasing 

 humidity, with moderate and equable warmth. The bird life of central 

 France (Allier) is similar to that bordering certain lakes of the interior of 

 Africa to-day.^ According to De Lapparent,- the Oligocenc terminated 



Fig. 78. 



■ Europe in Lower Oligocene or Sannoisian times. White = land. 

 Dotted areas = lagoons. After dc Lapparent, 1906. 



Ruled = sea. 



by the drying up of the lakes, deepening of the valleys, and beginning of the 

 river or fluviatile regime of the Lower Miocene. Thus the Oligocene of 

 Europe is physiographically subdivided as follows: 



3. Upper Oligocene. 



a 1. 



o I 



Middle Oligocene. 

 Lower Oligocene. 



Aquitaiiian. 



Stampian. 

 Sannoisian. 



Extensive freshwater lakes and 

 lagoons. Recession of sea. 



Advance of sea in Paris Basin. 

 Marine and brackish deposits 

 lacustrine and marine marls. 



Flora and Climate 



Europe. — A new character is given to the Oligocene flora by the disap- 

 pearance of many tropical forms, and the appearance of a great many 

 non-tropical forms; with few exceptions this flora has its modern repre- 

 sentatives north of the Equator.^ The temperature fell somewhat, and 



1 Milne Edwards, A., Recherches Anatomiques et Paleontologiques pour servir a I'Histoire 

 des Oiseaux Fossiles de la France. Paris, 1869-1871, p. 570. 



^ De Lapparent, A., Traite de Geologie, 1906, p. 1598. 



^ Schimper und Schenk, Handbuch der Palaeontologie, ed. by von Zittel, Pt. II, 1, Pal- 

 SBophytologie, 1890, p. 802. 



