Professor Favre on the Geotoc/y of the German Tyrol. 83 



stone we generally find the muschelkalk, the rock of which 

 is a pretty compact limestone ; sometimes, however, it oc- 

 curs in reniform masses, nests, or crusts, of a greenish sub- 

 stance, which resembles decomposed pyroxene, and in which 

 we observe fragments of pyroxene. 



It is evidently to the trias system, and more especially to 

 the muschelkalk, that we must refer the celebrated fossil 

 beds of 8t Cassian. These beds have not the least con- 

 nexion, in their geological position, with the neocomian forma- 

 tion, in which some geologists have endeavoured to classify 

 them. The locality richest in fossils is Steurs, situate two 

 hours to the south of St Cassian, on the summit of the 

 hills, clothed with pasture and woods, which separate the 

 valley of the Badia from that of Livinalongo (likewise called 

 Buchenstein or Fodom), near the sources of the Gader. The 

 position of the beds which contain these fossils, and of those 

 corresponding with them, becomes evident when we arrive 

 at St Cassian by the Grodner-Thal, in passing the Col de 

 Colfosco. These beds are situate, undoubtedly, below the 

 dolomitic masses. They do not always contain the fossils 

 which abound at St Cassian, and the variability of their cha- 

 racters, caused by the greater or less abundance of the 

 elements, arising from the submarine eruptions which have 

 taken place in their neighbourhood, are the principal obsta- 

 cles to their being recognised over a large extent. How- 

 ever, M. Emmerich has found some fossils of St Cassian 

 above St Michel, and in the ravine at Pufl, 



If the hills of Steurs, where the St Cassian fossils are 

 found, are not covered by dolomite, it must be ascribed to 

 an immense denudation which has carried off the latter rock. 



These fossiliferous beds are remarkable for the curious 

 association of othoceratites with ammonites, and the develop- 

 ment of a mass of small shells, which, for the most part, ap- 

 pear to be young. We have ourselves collected these fossils, 

 and their position altogether excludes the idea of a remanie- 

 ment dans les terrains. 



On examining the position of these fossil beds, we per- 

 ceive that, in the bottom of the valley of St Cassian, the 

 pyroxenic conglomerate occurs covered by varied sandstones, 



