M. Ogilvie Gordon — Fauna of Upper Cassian, South Tyrol. 347 



can only represent a small part of the fauna, but they at least cannot 

 be common. 



A similar impression of narrow spacial limitation is given by each 

 of the local developments of a fossil iferous Upper Cassian zone, at 

 Heilig Kreuz, Seeland Alpe, Misurina, and Eimbianco. This horizon 

 of Upper Triassic time is characterized, therefore, not only by 

 marked differences in the local lithological facies, but also by 

 marked local specializations in the aspect of contemporaneous faunas 

 inhabiting neighbouring seas and lagoons. Many of the fossils have 

 affinity with Cassian or Raibl species, yet can neither be identified 

 with, nor clearly distinguished from these. Hence, we may regard it 

 as probable that those specialized Upper Cassian faunas included, 

 amongst the species peculiar to themselves, certain types due tO' 

 strong adaptation or to retrogression. And we may learn from 

 the faunas of the Upper Cassian zone, no less than from those of 

 the higher Eaibl zones, that there are biological questions in South 

 Tyrol which concern the occurrence of pelagic and of littoral faunas 

 as local colonies in a neighbourhood of very unequal depth and 

 subject to volcanic interruptions in the form of lavas, tuffs, and fine 

 volcanic sand. These questions are one with the consideration of 

 lithological facies in the same district. 



The following table of Upper Trias strata in South Tyrol repre- 

 sents the zonal succession and local occurrence of facies as described 

 in former papers (cf. Geol. Mag., 1894:, PI. II, and Q.J.G.S., 

 1893, p. 16). 



Fassa-Schlern, 



south of the Buchenstein- 



Mahlknecht eruptive 



fractures. 



Within Enxeberg and Ampezzo, 



north of the Buchenstein-Mahlknecht eruptive 



fractures. 



^r 



Eaibl series. 



Dach 



Schlern Dolomite. 



^ I 



stein Dolomite. 



f or Upper Eaibl series (von Wohrmann), 

 with Ostrcea and Megalodus beds, 

 or Lower Eaibl series (von Wohrmann) , 

 equivalent to Upper Cardita series in, 

 Schlern , North Tyrol, represented by " red 

 Dolomite | Schlern Plateau fossiliferous series " or 

 by a varying thickness of stratitied 

 dolomite in South T}to1. 

 or Upper Cassian tufaceousseries(Ogilvie) , 

 L with Arimla beds. 

 Cassian series in ' Stuores ' development. 

 Wengen series, with Hahhia LoinincU. 



Upper Zone of Muschelkalk or Middle Trias. 



As, however. Baron von Wohrmann, in his comparative work on 

 " The Eaibl Strata," found the palasontological transition quite 

 gradual thi'oughout the Cardita and Eaibl zones in South Tyrol, he 

 included the whole series from the Halohia Lovnneli to tlie Oslraa 

 beds as Eaibl strata in wider sense (cf. " Uebersichtstabelle d. 



