Structure of the Eastern Alps. 411 



examined by M. Adolphe Brongniart, there is not one which is identical with 

 any known tertiary fossil plant in his collection*. 



10. All the deposits, so far enumerated, belong to highly inclined systems ; 

 but in the basins of Vienna and Styria the tertiary formations are nearly 

 horizontal, and may be subdivided into three groups. The lowest group, in 

 Styria (composed of marl, sand, and sandstone, in some instances passing into 

 a coarse conglomerate form) contains subordinate beds of lignite. It is ill 

 exposed in the Vienna basin. The middle group in both the basins is charac- 

 terized by the great masses of coralline limestone. In Styria the highest group 

 (essentially composed of sands, small pebble beds, shelly marls, highly calca- 

 reous marls passing into concretionary masses of limestone sometimes with a 

 true oolitic structure, &c.) alternates with matter ejected from the old volcanic 

 vents on the confines of Hungary. In the Vienna basin it is unmixed with 

 volcanic ejections; but is in some places separated from the middle group by 

 a deposit of fresh-water limestone. All the three groups contain bones of 

 Mammalia. The lowest we have compared with a portion of the deposits in 

 the London and Paris basins — the middle and upper, with the middle and 

 higher Sub-Apennine formations. The evidence for these several conclu- 

 sions is given in the details of the fifth chapter. Lastly, the highest regular 

 deposits of the Vienna basin are surmounted by beds of alluvial loam contain- 

 ing bones of extinct Mammalia mixed with terrestrial shells of living species. 



Such is a brief synopsis of the successive deposits noticed with greater or 

 less detail in the preceding chapters. 



Most of the accompanying sections afford the clearest proofs of the eleva- 

 tions and disruptions of the chain ; but they seldom give us any direct indi- 

 cation, either of the nature of the powers employed in producing these effects, 

 or of the exact points on which the principal moving forces have acted. In 

 the section through the ridges near the banks of the Iller we however find, 

 that volcanic dykes have struggled to force a vent through the secondary 

 strata ; and that they appear to have driven before them great masses of pri- 

 mary rock among the superincumbent deposits — thereby producing all the 

 ordinary accompaniments of contortion and elevation f. Coupling these 

 phenomena with the appearance of granite, and other undoubted igneous 

 rocks, within the region of the central axis, we have no hesitation in referring 

 all the great movements of the Alpine chain to certain modifications of igne- 



* Supra, p. 370—375, and p. 377—379. 

 t Supruy p. 333, and Plate XXXVI. fig. 4. 



3g2 



