210 



HISTORICAL PALEONTOLOGY. 



fossils. Sir Charles Lyell gives the following table of these 

 remarkable deposits : 



Strata below the Lias 



Kossen beds, 



(Synonyms, Up- 

 per St Cassian 

 beds of Escher 

 and Merian.) 



2. Dachstein beds. 



3. Hallstadt beds 

 (or St Cassian), 



4. A. Guttenstein 



beds. 

 B. Werfen beds, 



base of Upper 



Trias ? 

 Lower Trias of 



some geologists. 



in the Austrian Alps, in descending order. 



( Grey and black limestone, with calcar- 

 eous 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 con- 

 torta, Pecten Valoniensis, Cardium 

 Rh&ticum, Avicula inaquivalvis, Spir- 

 ifer Munsteri, Dev. Strata contain- 

 ing the above fossils alternate with 

 the Dachstein beds, lying next below. 



White or greyish limestone, often in 

 beds three or four feet thick. Total 

 thickness of the formation above 

 2000 feet. Upper part fossiliferous, 

 with some strata composed of corals 

 (Lithodendron.) Lower portion with- 

 out fossils. Among the character- 

 istic shells are Hemicardium Wulfeni, 

 Megalodon triqueter, and other large 

 bivalves. 



Red, pink, or white marbles, from 800 

 to 1000 feet in thickness, containing 

 more than 800 species of marine fos- 

 sils, for the most part mollusca. Many 

 species of Orthoceras. True Am- 

 monites, besides Ceratites and Gon- 

 iatites, Belemnites (rare), Porcellia, 

 Pleurotomaria, Trochus,Monotis Sali- 

 11 ana, &c 



A. Black and grey 

 limestone 150 feet 

 thick, alternating with 

 the underlying Wer- 

 fen beds. 



B. Red and green 

 shale and sandstone, 

 with salt and gyp- 

 sum. 



Among the fossils 

 are Ceratite* 

 cassianua. My- 

 acites fassaen- 

 8i8, Naticella 

 costata, dec. 



J 



In the United States, rocks of Triassic age occur in several 

 areas between the Appalachians and the Atlantic seaboard; 

 but they show no such triple division as in Germany, and their 

 exact place in the system is uncertain. The rocks of these 

 areas consist of red sandstones, sometimes shaly or conglomer- 

 atic, occasionally with beds of impure limestone. Other more 

 extensive areas where Triassic rocks appear at the surface, are 

 found west of the Mississippi, on the slopes of the Rocky Moun- 



