SUESS KOSSEN BRACHIOPODA. 33 



be searched after if not on the opposite side of the central mass* ? 

 The fauna of the Koessen strata is no more favourable to the hypo- 

 thesis of a former continent on the region at present occupied by the 

 Alps, than is the petrographical character of the limestones them- 

 selves, which, even on this spot, show a particular degree of purity. 



III. Gresten Strata. 



Black, marly limestones and dark sandstones, with rich coal-beds 

 and liassic fossils, are found in the portion of our Alps nearest to the 

 southern extremity of the "Bohemian continent"; they contain these 

 Brachiopods — Spirifer rostratus, Sp. Muensteri, and Terebratula 

 cornuta, which species are also found in the Koessen strata, but no 

 other species are common to both groups. Other genuine liassic 

 fossils of the Gresten strata (for the most part determined by M. von 

 Hauer) are — Mactromya cardioides, Phill. sp., Cardinia Listeri, 

 Sow. sp., Pholadomya ambigua. Sow., Phol. Hausmanni, Goldf., 

 Phol. decor at a, Hartm., Goniomya rhombifera, Goldf. sp., Pleu- 

 romyaunioides, Goldf. sp., Nucula complanata, Phill., Pinna foliumy 

 Young and Bird, Lima gig ant ea, Desh., and Pec ten liasinus, Nyst. ; 

 the following are common to the Gresten and Koessen strata — 

 Avicula intermedia, Nucula complanata, Pinna folium,Limagiganteay 

 and Pecten liasinus. They contain a rather considerable flora, in- 

 vestigated by MM. linger and v. Ettingshausen, many species of 

 which are known in the lias or the keuper of other countries. 



Generally the Gresten strata are very rich in bivalves, e. g Myce; 

 but, like the Koessen strata, are very deficient in Gasteropods and 

 Cephalopods ; yet the rich flora of the first indicates an essential 

 difference, confirmed by closer investigation. The Gresten strata 

 present a certain analogy with the keuper, as far as they bear the 

 character of deposits formed in the neighbourhood of a continent ; a 

 supposition strengthened by their rich coal-deposits. 



Plants only, and no molluscs, occur in the greater number of 

 localities. I have seen Brachiopods from Rohrbach (north-west of 

 Ilainfeld), from Gresten, from the Ferdinand-Stollen at Gaming, 

 and from the Eleonora-Schacht at Grossau ; and, farther south- 

 westward, from the environs of Weyer in the Pechgraben, especially 

 near Steinau ; and farther to the south-west, from the Furstenham- 

 mer. The ideal line, uniting the two most distant localities, Bern- 

 reuth and the Pechgraben, does not exceed ten (German) miles in 

 length. 



The researches as yet made are too few to allow of a farther dis- 

 cussion on the relations between the Gresten and the Koessen strata ; 

 these are more strictly separated, in palseontological as well in geo- 

 graphical respects, than any of the other groups mentioned in this 

 memoir, nor can their differences be sufliciently explained by the 

 influence of a neighbouring shore, until we find intermedial localities 



* No metaraorphic rocks, as they appear at the Radstiidter Tauern and at other 

 places, are at present known in the corresponding portion of the central mass; so 

 e. g. they are wanting at the foot of the Dachstein. 



