Geological Society. 49 



horizontal, have an estimated thickness of not less than 2G0'J feet, 

 and are shut in on all sides by Alpine limestone, forming on the 

 south a great serrated barrier, the highest pinnacles of which are 

 more than 10,000 feet above the level of the sea. 



The following abstract of detailed sections derived from the Horn 

 and the Ressenberg, exhibits the strata in descending order. 



1st. Red and green slaty, micaceous sandstone several hundred feet 

 thick (cap of the Horn). 



2nd. Green, micaceous, gritty sandstone extensively quarried as 

 whetstone, succeeded by yellowish, sandy marls (Ressenberg). 



3rd. A vast, shelly series consisting of blue marls alternating with 

 strong beds of com'pact limestone and calcareous grit, the upper 

 beds of wliich are marked by obscure traces of vegetables ; and the 

 middle and inferior strata, by a prodigious quantity of well pre- 

 served organic remains, out of which the authors collected upwards 

 of eighty species of bivalve and univalve shells, and fifteen species 

 of corals. (Localities :— beds of torrents descending into Gosau- 

 Thal.) 



4th. The above shelly series graduates downwards into beds of a 

 more conglomerate form which pass into a red sandstone and marl 

 containing gypsum ; and a coarse conglomerate, forming the base 

 of the whole system, rests upon, and abuts against, the alpine or 

 saliferous limestone. (Locality : — Russbach.) ^ 



Amongst the shells occurring in the group No. 3, are 

 Bifa/L-es .— Crassatella 2 species, Corbula 1, Pectunculus 3, Car- 

 dium 3, Plicatula 2, Gryphaea 2,Trigonia 2, Pecten 1, Solen 1, Ana- 

 tina I, Lucina 1, Astarte 1, Venus 2, Cypricardia 1, Isocardia 1, 

 Ostrea 2, Hippurites 2 *, &c. &c. 



C/nitaZucA' .— Melania 2, Melanopsis ? 1, Ampullaria 1, Neretma 1, 

 Natica3, Trochus 1, Turbo 1, Turritella 2, Cerithium 6, Nerita 2, 

 Turbinelia 1, Fusus 2, Rostellaria 1, Buccinum 3, Mitra 2, Volva- 

 ria 2, Conus ? 1 , &c. &c. 



Corals .— Turbinolia 1 , Caryophyllia 3, Fungia 2, Cyclohtes ? 2, 

 Astrea 5, Madrepora 2. »t -rv u 



The above organic remains have been examined by M. Deshayes 

 and Mr. J. Sowerby, neither of whom detected a single species 

 identical with any known fossil of the secondary rocks, whilst they 

 consider the greater number of the genera to be eminently charac- 

 teristic of the tertiary period.— The authors have further remarked 

 a strong resemblance between these fossils and certain unpubli>hed 

 species of the Vicentino, and Mr. Sowerby has identified a few species 

 with well-known tertiary shells. It is, therefore, concluded both from 

 negative and positive zoological evidence, as well as from the uncon- 

 formable position of the beds, that the whole deposit of Gosau must 

 be considered tertiary, or, in other words, younger than the chalk. 

 At the same time, the great proportion of new species contamed 

 therein, and the absence of those identifications with recent shells 



• The genas Hippurites is placed among the bivalves on the authority of 

 M. Dcshaves. 



N.S. Vol. 7. No. 87. Jan. 1830. H which 



