OF THE AUSTRIAN ALPS. 



661 



Infra-liassic{?) Strata of the Austrian Alps, in descending Order. 



Koessen beds. 



(Synonyms, Upper St. 

 Cassian beds of Escber and 

 Merian ; Upper Trias ? or 

 intermediate between Lias 

 and Trias ?) 



2. Dacbstein beds, 



between Lias and Trias ? " 



3. Hallstatt beds 

 (or St. Cassian). 

 Trias. 



Upper 



' Gray and black limestone with calcareous marls, 

 having a thickness of about 50 feet. Among 

 the fossils, Brachiopoda very numerous ; some 

 few species common to the genuine Lias ; many 

 peculiar. Avicula contorta, Pecten Valoniensis, 

 Cardium Bkceticum, Avicula incequivalvis, Spirifer 

 Munsteri, Dav. Strata containing the above 

 fossils alternate with the Dachstein beds, lying 

 next below. 



White or grayish limestone, often in beds 3 or 4 

 feet thick. Total thickness of the formation 

 above 2000 feet. Upper part fossiliferous, with 

 some strata composed of corals. (Lithodendron.) 

 Lower portion without fossils. Among the 

 characteristic shells are Hemicardium Wulferii, 

 Megalodon triqueter, and other large bivalves. 



Eed, pink, or white marble, from 800 to 1000 

 feet in thickness, containing more than 800 

 species of marine fossils, for the most part mol- 

 lusca. Many species of Orthoceras. True Am- 

 monites, besides Ceratites and Gonialites, Belemnites 

 (rare), Porcellia, Pleurotomaria, Trochus, Monotis 

 salinaria, &c. 



4. A. Guttenstein beds. 

 B. Werfen beds, 



base of Upper 

 Trias ? Lower Trias 

 of some geologists. 



A. Black and gray limestone 

 150 feet thick, alternating 

 with the underlying Wer- 

 fen beds. 



B. Bed and green shale and 

 sandstone with Salt and 

 Gypsum. 



Among the fossils are 

 Ceratites cassianus, Mya- 

 cites fassaensis, Naticella 

 costata, &c. 



In regard to the age of the rocks above mentioned, the Koessen and 

 Dachstein beds are referred by some to the Lias, by others to the Trias, 

 while many consider them to be of intermediate date. According to 

 Mr. Suess, the Koessen beds correspond to the upper bone-bed of Swabia, 

 in -which the Microlestes was found (see p. 341), but it should not be 

 forgotten that that stratum contains true triassic species of reptiles and 

 fish. On the whole, the beds 1 and 2 contain a very peculiar fauna, 

 and Mr. Suess remarks that some of the fossils are identical with the 

 Irish "Portrush beds" of Colonel Portlock, described in his Eeport on 

 Londonderry. The Koessen beds have been traced for 100 geographi- 

 cal miles from near Geneva to the environs of Vienna. 



"Whatever doubts may be entertained respecting the exact age of the 

 beds Nos. 1 and 2, there is now no longer any dispute that the Hallstatt 

 and St. Cassian beds agree in age with the Keuper or Upper Trias ; but 

 whether the Werfen sandstone, No. 4, should form part of the same 

 series, or, as Von Hauer inclines to believe, should be classed as the 

 equivalent of " the Bunter or Lower Trias," is still undetermined. The 

 absence of well-characterized Muschelkalk fossils in the Austrian Alps 

 renders this point very difficult to decide. Rich deposits of salt, asso- 

 ciated with the Werfen beds, incline some geologists to presume that 

 they belong to the Upper Trias. Should they be classed as " Bunter," 

 the Guttenstein limestone would then correspond in position with the 

 Muschelkalk, but no Muschelkalk fossils have ever been met with in it 



