468 HISTORY OF GEOLOGY AND PALAEONTOLOGY. 



Pufls Ravine to the Seis Alp, and in the Gader Valley ; by 

 this means he ascertained that the "Seis Strata" begin with 

 alternating dark-red and white sandstone, pass upward into 

 red calcareous, micaceous, and thin-bedded shales with 

 Myacites Fassaensis, and these are succeeded by a complex 

 of grey calcareous beds resembling " Wellenkalk," containing 

 Posidonomya Clarai. 



The succession of strata, as Emmrich recognised it, may be 

 shortly tabulated 



7. Dolomite. 



6. Fossiliferous St. Cassian Strata, which build up the 



Seis Alp, and nearer Schlern at the Cipit Stream 



yield numerous fossils. 

 5. Wengen Strata ivith Halobia Lommeli. 

 4. Unfossiliferous Complex. 



(/.) Calcareous .rock resembling Wellenkalk. 



(<?.) Dark limestone and siliceous concretions. 



(d.) Light grey shaly limestone. 



(<r.) Dark bituminous limestone. 



(b.) Dolomite. 



(a.) Limestone with irregular bedding surfaces. 

 3. Limestone with Posidonomya Clarai. 

 2. Shales with Myacites Fassaensis. 

 i. Seis Sandstone. 



Emmrich's succession was taken as the model by all subse- 

 quent stratigraphers, and became rapidly recognised as the 

 normal section of the South Tyrol Trias. Thus the interest 

 aroused by the St. Cassian fossils had culminated in providing 

 the first clue to the particular character of the difficulties which 

 had to be faced in Alpine geology. The Alpine equivalents of 

 the Bunter or lower Trias had been clearly elucidated, the 

 Muschelkalk had been identified; and the Wengen-Cassian 

 group above it had demonstrated the actual presence of a 

 fauna and a lithological succession different from that presented 

 in the Muschelkalk or succeeding horizons in any known 

 extra-Alpine area. The principle of local developments of 

 rock of contemporaneous origin, but containing distinctive 

 faunal assemblages, was now appreciated, and geologists had 

 also more hope of being able to fix the relative age of masses of 

 "Alpine Limestone" according to their stratigraphical position 

 below or above the fossiliferous Wengen-Cassian group 



