The Dipneusti and Crossopterygii 313 



nia, und Corbida und wijrde von oberem Alpenkalke be- 

 deckt," 



The associated plant-remains were Noeggerathia voge- 

 siaca, P'oltzia heterophylla, Pterophyllum minus, Taeni- 

 opteris marantacea, an undetermined fern, etc.; and all indi- 

 cate an upper Keuper or Lower Liassic affinity. 



The history of the entire series of associated strata we 

 would interpret as follows: In succession to a marine group 

 of beds, and through elevation of land, a considerable area 

 became a basin into which freshwaters discharged. This 

 basin contained, or had swept into it, a multitude of fishes 

 — all of freshwater habitat. From some sudden terrene 

 — probably volcanic action, these were suddenly killed in 

 vast quantities, were mixed with remains of land plants 

 from surrounding lake-margins, and were rapidly covered 

 over by a volcanic ash-deposit. The bed thus formed was 

 next depressed below sea-level, and a marine deposit was 

 laid down that was rich in typical marine organisms but for 

 a clear reason not in fishes, as given above. Through sub- 

 sequent deposit and pressure of added beds, as well as in 

 all likelihood from generation of high temperatures by 

 volcanic agency or grinding and faulting of the rock-masses, 

 decomposition of the fish-oils that had been set free from 

 the entombed fishes took place, with formation of abundant 

 bituminous material. 



So while — as will be fully dealt with later — the fish 

 beds of Comen near Gorz, and their organisms are evi- 

 dently marine, we accept it, from similar evidence as the 

 above, that the bituminous beds of Raibl, Besano, Giffoni, 

 Perledo, etc. all contained freshwater fishes, and the ana- 

 lyzed fixed or fatty oils of these gave the bituminous 

 character to the rocks themselves that has in part made them 

 famous. This completely correlates them also ecologically 

 with the similar — probably contemporaneous — rocks of 

 New Jersey and Connecticut. As regards the Solenhofen 

 and similar types of stratum, these contain so heterogeneous 

 an assembled mass of land, freshwater and marine remains, 

 that we claim for the enclosed examples of Heptanema, 

 Graphiurus, Undina, Libys and Coccoderma, a freshwater 



