Yenetia during the Neogene. 305 



Yenetian gulf shows insignificant differences due to locdl races 

 or varieties. 



The terrestrial faunas are naost striking, at least from a paleo- 

 geographic point of view. The relative frequency of species 

 identical to or closely allied with those of the Rhone Yalley, 

 of Switzerland and of the Vienna Basin, associated with others 

 of still wider range, proves that the Alpine region at that time 

 formed probably a single biological province. These conti- 

 nental faunas of the Pontiau, as well as those strictly litcoral 

 ones of the upper Tortonian, by their similarities indicate very 

 close relationships with the faunas living today in the warm 

 countries of the " ancien continent" (Melania, Terebralia), 

 although one could cite as well in Trivia a bond of union with 

 the faunas of North America, due probably to some collateral 

 phylum of slow evolution. 



Succession of fades. 



Some very interesting conclusions can be drawn from a study 

 of the succession of facies in the Neogene series (see table fig. 

 2), and from their geographical distri})ution during each stage 

 of this period. 



The Miocene beds of Yenetia represent a complete cycle of 

 sedimentation. The series commences in the lower Miocene 

 with '' molasses " of shallow water origin in the center of the 

 gulf, by littoral conglomerates or sands along the shores. A 

 differeuce of facies is evident from a comparative study of the 

 rocks, it is confirmed by certain details of the fauna. I shall 

 cite only one illustration — the near shore barnacles, which with 

 the Nullipores abound in the beds of the Aquitanian and of 

 the lower Langhian in the intra-alpine remnants, but are always 

 replaced in the extra-alpine deposits by species of the same 

 genus, but living on sponges or on shells, and consequently 

 able to live in an environment farther removed from the shore. 



But on this rocky foundation, with beating waters, rich in 

 organisms, peopled with sharks, cetaceans, and sirenians, the 

 depth rapidly increased; in the center of the basin the psam- 

 mophyllic (sandy) faunas with Clypeasters and Scutellas are 

 replaced before the end of the Aquitanian by Spatangids, 

 Pholadomyas, and Pleurotomids. 



At the end of the Langhian the depth reached its maxhnum^ 

 and in the marly or marly-calcareous beds of this stage abound 

 the simple corals, Pinodonta, and in the extra-alpine region, 

 Cephalopods (Aturia, Nautilus) and bathyal Cirripedia. In 

 the intra-alpine region, on the contrary, in spite of its consider- 

 able depth, the shore is still reasonably near: here and there 

 (Belluno) the large and deep estuary of a stream of some import- 



