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THE AMERICAN NATURALIST [Vol. XL1I 



Cephalogale), of Amphicyoninae (Amphicyon), of Mus- 

 telidse (Stenogale, Palaeogale, Stenoplesictis), of Lutrinai 

 (Lutrictis, Lutra), of Felidae (Pseudaglurus, Muchairodus). 



2. Very Important African or Afro-Asiatic Migra- 

 tions of Proboscidea (Mastodon, Dinotherium), of Anti- 

 lopinae (Protragocerus), of certain Cervulinae (Micro- 

 meryx), of some Rhinocerotidae (Teleoceras, Ceratorhi- 

 nus), of some Suidae ( Chcerotherium, Listriodon), and of 

 anthropoid apes (Pliopithecus). 



3. North American Migration of Equidse (Anchithe- 



II. Middle Miocene (Vindobonian, divisible into three 

 substages: Helvetian, Tortonian, Sarmatian). Corre- 

 sponding to these three substages are three mammalian 

 faunae, grading into one another by almost imperceptible 

 transitions. These assemblages may be denoted as fol- 

 lows, the names being derived from those localities in the 

 sub-Pyrenean basin where each is typically represented : 

 (1) horizon of Sansan, (2) horizon of Simorre, (3) hori- 

 zon of Saint-Gaudens. 



1. Horizon of Sansan.— Principal localities: Sansan, 

 Jegun (Gers), calcareous marls of the Loire (Pontlevoy, 

 Sainte-Maure, Manthelan) ; marine Molasse of the en- 

 virons of Romans (pont de l'Herbasse, Bren, Clerieux) ; 

 marine Molasse of Suabia (Baltringen, Rammingen, 

 Heggbach, Hausen; Niederstozingen, Siissen, Ursendorf, 

 Hochgeland) ; of the lignites of Styria (Eibiswald, Go- 

 riach, Wies, Voitsberg, Gamlitz, Parschlug, Neufel) and 

 of Lower Austria (Leoben, Leiding, Feisternitz, marine 

 sands of Grand at Guntersdorf ) ; Georgengsmund (Ba- 

 varia), Engelswies (Baden). 



2. Horizon of Simorre.— Principal localities: Simorre, 

 Bonnefond, St. Cristan, Tournon, Villefranche d'Astarac, 

 rile-en-Dodon (Gers); Saverdun (Ariege) ; marine de- 

 posits of Mirabeau ( Basses- Al pes), of Sorgues (Vau- 

 ■cluse), of Romans (Drome) ; Steinheim, Nordlingen, Ries, 

 Althausen, Urlau (Suabia) ; Hohenhoven (Baden) ; intra- 



