THE TRIASSIC 8YSTKM 349 



lion which exists in the Tyrol and extends throughout Southern 

 Europe. 



Moreover, this marine facies has a wide extension over other 

 parts of the world ; it spreads through Southern Europe from 

 Spain to Hungary and the Balkans ; it is found in Turkestan, 

 Central Asia, and the Himalayas, and a similar marine Triassic 

 System occurs in Siberia, Japan, North America, and again south - 

 \\anl in Columbia, Peru, New Zealand, and Australia. In South 

 Africa, in South India, and in Argentina red sandstones with 

 ivptilinu ivinains are found, and these regions seem to have formed 

 part of other Triassic continents. In this volume, however, it is 

 only possible to give a brief account of the European Trias. 



The name Trias, as will be seen, is not a good one, being really 

 applicable to the German facies only, which is a limited and excep- 

 tional one. A nomenclature capable of wider application will 

 doubtless be eventually proposed, and must, of course, be based on 

 the pelagic development of the system. From the recent work of 

 Mojsissovics, Waagen, and Diener on the distribution of the fossils 

 in the pelagic facies, it appears that the system falls more naturally 

 into two great divisions, a lower and an upper, each of which is 

 again divisible into two series. 



B. LIFE OP THE PERIOD 



1. The Marine Fauna 



The fauna of the Alpine and Tyrolian Trias, though consisting 

 mainly of Neozoic forms of life, yet includes some survivors of 

 Palaeozoic types ; the proportion of species belonging to genera which 

 are essentially Palaeozoic being stated as only one-tenth of the total 

 number of species composing the fauna. 



The Cephalopoda are a remarkable assemblage. A single species 

 of Orthoceras with some of Temnocheilus and Pleuronautilus connect 

 it with Palaeozoic faunas, while the genus Nautilus (as now 

 restricted) makes its first appearance. The Ammonoidea, however, 

 are the dominant forms, and include many genera with nearly simple 

 lobes and saddles, such as Ceratites, Lobites, Tirolites, Trachyceras, 

 Tropites, as well as genera with more complex lobes, such as Arcestes, 

 Cladiscites, Ptychites, Pinacoceras, Phylloceras, Rhacophyllites, and 

 Megaphyllites. Dibranchiate Cephalopoda make their first appear- 

 ance and are represented by precursors of the Belemnitidie in 

 Aulacoceras and Atractites. 



Gastropoda are abundant, and include representatives of the 

 Palaeozoic genera Murchisonia, Loxonema, Naticopsis, and Euom- 



