348 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [April 5, 



coloured and harder limestones, which nevertheless are generally 

 characterized by a certain amount of aluminous contents. 



In different places there are found in this formation very remark- 

 able and extensive strata of a finely-grained grey sandstone, becoming 

 brown by decomposition ; it contains little pieces of mica, and either 

 effervesces but slightly, or not at all, with acids. These sandstones 

 contain few fossils ; I found only some indistinct vegetable impres- 

 sions and fragments of AvicuJa and Nucida. 



By investigating the superposition and the mutual relations of the 

 strata, I came to the conclusion that these sandstones were to be 

 considered as a part of the Lower Lias formation. 



These sandstones seemed to me to be very analogous with those 

 which in the Vorarlberg and in Austria accompany the " alpine coal," 

 according to Escher and Von Hauer. M. Hauer replied to my 

 suggestions, upon making these comparisons, that he also was inclined 

 to admit, after the inspection of the specimens I had sent him, such 

 an analogy, and that in Austria the sandstones accompanying what 

 was termed alpine coal (iVlpenkohle) were now also considered as a 

 part of the Lower Lias formation, though with a different yac«eA', and 

 in many respects a different fauna. 



All the strata here spoken of, I have laid down on the map under 

 the name of "Lower Lias," which was first used by M. Hauer of 

 Vienna, who admits that these strata must be separated from the 

 Cassian beds, which form the uppermost part of the alpine Trias and 

 contain a very different faima. Other geologists, Emmrich, Escher, 

 and Merian, are inclined to consider these as an equivalent of the 

 Cassian strata. They endeavour to infer this from the mode of 

 superposition in the southern Alps, and from analogy in some 

 palseontological characters. 



According to the recent investigations in the Austrian and in the 

 Bavarian Alps, it seems that we must consider as Upper Muschel- 

 kalk the strata of Hallstadt, forming an equivalent of the Cassian 

 beds of Miinster and Klipstein -with Ammonites Aon, &c. 



The Lower Lias is considered to comprise as contemporaneous 

 deposits : 



a. The strata of Kossen = Gervillia-strata of Prof, Emmrich = 

 upper Cassian beds of the Swiss geologists. 



b. The Dachstein-limestones with Cardium triquetrum {^=Mega- 

 lodiis scntatus, Schaf haiitl) . 



The fossiliferous portions of the alpine Trias not being exposed 

 in that part of the mountains to which I more closely directed my 

 investigations, I could not obtain any proofs of the relation of the 

 Gervillia-beds and their fauna to that of the lower formations. 



The strata of the inferior Lias are in many places very rich in 

 organic remains ; the follo'n'ing is a list of the most characteristic and 

 generally distributed of these fossils. They have been collected and 

 determined by myself. Fortunately I was enabletl to send specimens 

 of all of them to M. Hauer, who has compared them with the beau- 

 tiful collection of alpine fossils now accunudating at Vienna. 



Annnoniles Robcrti, Hauer; vcrv distincllv found in this forma- 



