174 



Evolution and Distribution of P^ishes 



teeth, bony plates, scales and dental spines were alone left 

 in countless numbers as main constituents of each bone-bed. 



The above view is eminently favored by such a section 

 as that given in Arthaber's article on the Raibl fish- 

 deposits. It is here seen that (725:298) the fish-strata 

 lie between an upper and a lower marine band, the latter 

 with corals and echinoids, the former with marine molluscs. 

 The freshwater zone includes typical land plants, also the 

 fishes Pholidopleiirus typus, Belonorhynchiis striolatus and 

 Ptycholepis raiblensis. 



But another and equally noteworthy feature of the 

 Trias, that is connected also with the above bone-beds as 

 we believe, is the occurrence, in midst of marine dolomitic 

 strata, of deposits rich in fish and reptilian remains, but 

 characterized further by their highly bituminous and even 

 asphaltic quality. The bituminous beds at Besano near 

 Lake Lugano, the Perledo beds near Lake Como, the Lu- 

 mezzane beds in Lombardy, the Giffoni beds of Salerno, 

 the Tyrolese beds of Seefeld, and the Raibl beds in Car- 

 inthia, are all highly bituminous. As noted below also the 

 Upper Triassic beds of Eastern America are often of like 

 nature. Deeke, Basano, Kner, Newberry and others have 

 described the rich fish-fauna that characterizes these beds. 

 Such genera as Heterolepidotus, Lepidotiis, Semionotiis 

 (Fig. 22), Pholidophorus, Coelacanthus, Catoptenis, Dicty- 

 opyge and Belonorhynchiis are typical. All of these genera 

 were of freshwater habitat. 



Fig. 22. Semionotus {Ischyptenis) agassizii. A Triassic fish 

 common to the rocks of New Jersey and New England. About 

 one-third natural size. (Reduced from Eastman). 



