XIV INTRODUCTION. 



As a compromise, which has the convenience of avoiding the 

 necessity of abolishing the term Middle Miocene 1 , which has become 

 almost a classic one through the labours of the French paleontolo- 

 gists, the term Upper Miocene may be retained for the (Eningen or 

 higher beds of the Upper Swiss freshwater molasse 2 , which connect 

 the Eppelsheim beds with the typical Middle Miocene of Prance, and 

 are placed by some geologists in the Miocene 3 , and by others 4 at 

 the base of the Pliocene with the Eppelsheim beds. The lower beds 

 of the upper Swiss molasse (Kiipfnach, Elgg, &c), which were in- 

 cluded by Heer in his (Eningen stage, appear to correspond to the 

 French Middle Miocene. The Congerian stage of the Vienna Basin 

 is included in the Lower Pliocene, while the Sarmatian and Mediter- 

 ranean (Leithakalk) stages of the same region are mainly classed with 

 the upper part of the Middle Miocene ; the Upper Sarmatian stage 

 probably, however, corresponds in part with the (Eningen beds, 

 while the Mediterranean stage probably contains representatives of 

 group B. It is, however, necessary to mention that the classification 

 adopted is to a considerable extent a faunal one, and that, owing to 

 regional distribution, the fauna of one group may in some instances 

 be contemporaneous with that of another group. This appears to 

 be the case with the mammals of Pikermi, which have been shown 

 by Fuchs 5 to occur in a comparatively Ijiigh Pliocene horizon, and 

 in reality, therefore, were probably contemporaries of the more 

 advanced fauna of other parts of Europe, but our knowledge is at 

 present insufficient to indicate the relations of the fauna of some 

 of the other deposits placed in the same group. A well-known 



Tortonian stage (Gaudry, ' Animaux Fossiles et Geologie du Mont Leberon,' 

 p. 106), which is the equivalent of the Pliocene Congerian (Inzersdorf and 

 Belvedere) stage of the Vienna Basin (see Oredner, ' Eleinente der Geologie,' 

 5th ed. p. 707). Some English geologists (Geikie and Duncan) retain, how- 

 ever, the Vaucluse beds in the Upper Miocene. The Concud beds of Spain, and 

 those of Baltavar in Hungary, as well as those of Maragha in Persia, are placed 

 in the same group with the Pikermi beds solely on account of the similarity of 

 their Mammalian fauna. 



1 If the term Upper Miocene were adopted for these beds, it would probably 

 lead to confusion, as it would not correspond with the Upper Miocene of the 

 French geologists. 



2 The beds at Ccrdagne (Pyrenees-Orientales) are probably approximately 

 equivalent. 



3 Duncan, ' Lyell's Elements of Geology,' 4th ed. p. 184 (1885), and Geikie, 

 1 Text-book of Geology,' 1st ed. pp. 807-8 (1882). 



4 Credner, ' Elemente der Geologie,' 5th ed. p. 696 (1883). 



r ' See Blanford, Presidential Address to Gcol. Sect. British Association, 1884. 



