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of the tertiary formations on the southern flank of the Alps between 

 the Brenta and the Piave. They are divided into two great natural 

 groups exhibited in two zones : — an outer zone containing shells which 

 seem to be nearly identical with the well known fossils of the newer 

 tertiary Sub-Apennine formations; — an inner and inferior zone con- 

 taining in its higher portions a few shells resembling those of a part 

 of the Bourdeaux basin, while its lower beds are distinguished by 

 innumerable organic remains, more than half of which seem to be 

 specifically identical with those of the calcaire grossier or London 

 clay. These lower beds on the banks of the Brenta are inclined at 

 70° or 80°, and are based upon a nummulite rock, which is abso- 

 lutely vertical and conformable to the scaglia (containing ammonites 

 and belemnites), and together with it rises into peaks of considerable 

 height on the extreme border of the chain : and there is no conglo- 

 merate or other mechanical degradation of the older rocks, to mark 

 the junction of the secondary and tertiary systems. Some notion 

 may be formed of the enormous thickness of these deposits from the 

 statement, that a transverse section (from Asolo to Possagno) through 

 beds of only a part of this series, inclined at various angles from 25° 

 to 40° and exhibiting no invertions of dip, is not less than five miles 

 in length. One important consequence seems to follow inevitably 

 from these details : the last epoch of elevation of the neighbouring- 

 mountains must have commmenced during a period posterior to the 

 tertiary formations described in this memoir. 



In three Papers, recently presented by Mr. Murchison and myself 

 to this Society, we have endeavoured to establish a series of similar 

 conclusions, by induction from the phenomena observed on the flanks 

 of the Salzburg and Bavarian Alps. I will not give you any analy- 

 sis of details, so lately the subject of discussion in this room. I may, 

 however, briefly recall your attention to the results which we con- 

 sider best established and of most importance. We have shown 

 that several transverse sections from the central axis of the Alps to 

 the basin of the Upper Danube would present a succession of phe- 

 nomena in very near accordance with those of other transverse 

 sections from the same axis to the tertiary formations at the other 

 base of the chain in the north of Italy. On both sides of this chain, 

 after passing over the great secondary calcareous zones, we meet 

 with the lower tertiary strata, — always highly inclined, sometimes 

 vertical, and occasionally conformable to the beds of the older sys- 

 tem. We contend that this remarkable symmetry confirms the hy- 

 pothesis of a recent elevation of the Eastern Alps - } and makes it pro- 

 bable, independently of arguments derived from organic remains, that 

 the tertiary deposits of the Sub-Apennine regions and of the basin 

 of the Upper Danube belong to one period of formation. 



Thick masses of strata full of organic remains, and often occurring 

 at low levels near the northern foot of the chain, are sometimes also 

 found (e. g. in the valley of Gosau) in unconformable positions, 

 caught up among the serrated peaks of the Alps, four or five thousand 

 feet above the level of the sea. Such a disjunction of corresponding 

 strata (and I may observe that the argument bears not upon their 



