332 NATURAL SCIENCE [xMay 



such as Anthracotherium, HyoiMamus, and Elotlierium, both in Europe 

 and America. The early ruminants are also represented in Europe 

 by such genera as Caenotherium and Amphitragulus ; while they 

 occur in still greater variety in North America as Oreodonts 

 {Oreodon and Agriochoerus), primitive camels {Poebrothcrium), and 

 strangely horned quadrupeds {Frotoceras). The opossum {Dideliohys) 

 appears for the last time in Europe ; so also do the modern American 

 freshwater ganoid fishes, Amia and Lepidosteus. Among marine 

 mammals, Hrditherium and Miosircn, from the neighbourhood of 

 Mayence and Antwerp respectively, are the earliest well-known 

 examples of the Sirenia. 



The Middle Miocene fauna is well known from numerous 

 localities in Europe, and of these some of the more classical may 

 be enumerated as follows : Sansan, Simorre, and Villefranche 

 d'Astarac, in Gers, France ; Leognau and Romans, Gironde ; St 

 Gaudens, Haute Garonne ; La Grive-St-Alban, Isere ; Montpellier, 

 Herault ; Kapfnach, Chauxdefonds, and Elgg, in Switzerland ; 

 Georgensgniiind and Steinheim, in Wltrtemberg ; and Monte Bam- 

 boli, in Tuscany. In Xorth America the John Day Formation of 

 Oregon and Montana is supposed to furnish a nearly equivalent, 

 though distinctly more ancient assemblage of mammals. The most 

 remarkable feature of this fauna in Europe is the sudden appearance 

 of the elephants or Proboscidea {Dinothcrium and Mastodon) and the 

 true apes (Orcojnthecus, Dri/opithccus). It is also interesting as com- 

 prising the earliest known deer with antlers (Dicroccrus), and the 

 earliest rhinoceroses with a horn. The Carnivora are noteworthy 

 as including a series of genera intermediate between the dogs and 

 bears (Amphicijon, Hyacnarctos). In North America there are not 

 as yet any traces of the Proboscidea, or of deer with antlers ; while 

 the chief Carnivora of the John .Day Formation are the sabre- 

 toothed cats {Nimravus). 



There is no clearly distinguishable Upper Miocene mammalian 

 fauna in Europe, though the lacustrine deposits of Oeningen, Baden, 

 may perhaps represent this stage. In North America, however, the 

 mammals from the Loup Fork Formation are usually described as 

 Upper Miocene ; and the assemblage or fauna certainly exhibits a 

 mingling of the types which are partly Middle Miocene, partly 

 Lower Pliocene, in Europe. The Loup Fork series is chiefly of 

 lacustrine origin, and very widely distributed between South Dakota 

 and Mexico. Mastodon now appears for the first time in the New 

 World, but it is not accompanied by Linotherium. The rhino- 

 ceroses are still hornless. Besides other genera of primitive horses, 

 Hipparion is found. Deer with small antlers are also met with 

 (Cosorip:); while Frocamelus makes a very close approach to the 

 camels, which appear in India in the Pliocene. 



