20 GEOLOGICAL MEMOIRS. 



The Halobia-schist, No. 16 (Lettenkohle), consists of black marl- 

 slates, and affords the following fossils : — 



Bactryllium Schmidii, Heer. Ammonites globosi. 



B. Merianii, Heer. Halobia Lommellii, Wissm. 



It contains also gypsum (in the Rellsthal), granular dolomites, and 

 nodules of marly limestone enclosing Pecten, Cardinia ?, and Me- 

 lania ? 



A series of Quartzose Sandstones and Black Slates, No. 1 7, hardly 

 admits of separation from the preceding ; it appears even to alternate 

 with it; hence the author is of opinion that Nos. 16 and 17 niay 

 represent alternations of freshwater and marine deposits ; the latter 

 being freshwater, and No. 16 marine. This group may be parallel 

 with the Letten-kohle of the Keuper : it presents the following fos- 

 sils : — 



Equisetum columnare. Cycadites. 



Pterophyllum longifolium. Calamites arenaceus. 



P. Jaegeri. 



These, together with its lithological characters, refer it to the Keuper, 

 and a iish-tooth, which M. von Meyer considers to belong to a Tri- 

 assic fish, supplies additional evidence. This series is developed in 

 the Rellsthal, at Vadans, the Triesnerkulm, Dalaas, Bludenz, &c. 



The Muschelkalk, No. 18, appears only in the Lombard Alps. It 

 is characterized by 



Bactryllium canaliculatum. Myophoriae. 



Encrinites liliiformis. Ceratites. 



The Bunter Sandstone, No. 19, is seen at Regoledo, where it con- 

 tains Voltzia heterophylla, Bronn, and j^thophyllum speciosum, 

 Schimper. 



The Verrucano is very variable in composition. The chief mass 

 consists of a conglomerate, sometimes fine and sometimes coarse, of 

 pebbles of quartz, often coloured by oxide of iron. In the Rellsthal, 

 schists represent this series ; sometimes argillaceous, and sometimes 

 micaceous schists ; and near Vadans micaceous schist occurs in red 

 sandstone (at Hindelang, Vorderjoch, and Thannheim). The red 

 sandstone is the oldest sedimentary rock of the district. 



The metamorphic rocks are numerous in the Vorarlberg. The 

 following are the principal varieties. Black slates, often found 

 beneath the great dolomite. Talcose schist (Rhseticon, Valleys of 

 Samnia and Gamperton). Gypsum. Talcose rocks with garnets, 

 similar to those of Nuffenen. White limestones with hornblende. 

 Dolomite. Gneiss (Geisspitz, &c.). Spilite (between the Samnia 

 and Gamperton Valleys). 



From the author's observations it appears that in the central part 

 of the Grisons the rocks have a northern direction, and also in the 

 Paznaun Valley. Near Kappl, however, they appear to have a west 

 direction. 



In conclusion, it appears that the Coal-formation, represented. 



