G6 Sir R. I. Miu'cliisoii oyi the Vents oj Hut Vapour in Tuscany. 



and a coal formation*. It is certain, therefore, that the serpeutinous 

 eruption there found its issue along a line of fracture coincident with 

 the north and south direction whicli had hecu impressed upon these 

 lands at a very remote period — such eruption, though divergent from 

 them, heing simultaneous with the chief axes of upheaval in Italy. 



In speaking of divergent lines of fracture and elevacion, which 

 offer ])roofs of simultaneous eruption and dislocation, I am led to 

 terminate my communications on the Alps and Apennines, by calling 

 attention to the great pheenomena which are common to these two 

 chains and at the same time distinguish them. To render my idea 

 clear I have annexed the accom{)anying diagram, fig. G. Whilst the 

 direction of the chief ridges of Italy is more or less at right angles 

 to the main direction of the Alps, we know that the greatest amount 

 of metamorphism has been impressed on both chains after the imm- 

 mulitic period ; and again, that in both very violent movements 

 took place after the dej)osition of the miocene tertiary. In the chief 

 range of the Swiss and Austrian Alps, the greatest changes of me- 

 tamorphism, elevation, depression, and contortion have been deter- 

 mined upon lines having on the whole an east-north-east and west- 



* After this memoir was read, Professor Meneghini of Pisa communicated to 

 me, that Professor Savi and himself had discovered undoubted species of coal 

 plants (Pecupleris arborexcens and Annularia longifolia) in anthracite schists, 

 which on the right bank of the Era near Volterra form the lower part of the 

 " Verrucano," or oldest conglomerate of Italy. A communication to this effect, 

 on the part of his colleagues, was at the same time made by Professor Parlatore 

 at the late Meeting of the British Association at Edinburgh. This important 

 discovery seems to prove that a lower portion of the rocks called verrucano, which 

 have hitherto been considered to be the natural base of the lias, is of the same 

 pahcozoic age as the conglomerates of the Valorsine and other places in the Alps. 

 Yet still, in reference to my opinion above expressed, the plants found in Tuscany 

 may either have been derived from lands now submerged, or from adjacent shores, 

 of which the Silurian and ancient crystalline rocks of Sardinia and Corsica are 

 the existing remnants. At all events, no rocks have yet been made known to 

 geologists in Northern or Central Italy which are of sufficient antiquity to have 

 been the dry land whereon the coal plants grew, to which Professors Meneghini 

 and Savi have drawn attention. 



As Italy is thus connected still more closely with the Alps by the feature of an- 

 thracitic coal plants common to both countries, I would here allude to an able 

 recent memoir of Professor Heer (Mittheilungen der Natur. Gcsellscht. in Zurich, 

 1850), in which, specially referring to the case of Petit Coeur in Savoy, he argues, 

 that the plants found there being terrestrial and of the carboniferous aera, the 

 stratum in which they are imbed(ied cannot he united with that which contains 

 marine liassic belemnites. The general analogical reasoning of this author is so 

 much in unison with my wishes, as expressed in the Memoir on the Alps, Apen- 

 nines, and Carpathians (Journ. Geol. Soc. Lond. vol. v. pp. 176, 177), that I have 

 only to regret he should have omitted to acquaint his readers, that I drew my in- 

 ferences solely from the actual section and the order and position of the beds. I 

 clearly stated that I did so in opposition to my desire to find the plants and be- 

 lemnites lying in what might be considered sci)arate formations. With the utmost 

 deference to the value of organic remains, I felt however bound to affirm, that in 

 the example of Petit C(cur, the physical evidences seemed fairly to sustain the 

 views of Al. Elie de Beaumont and i\I. Sismonda. At the same time, I did not 

 deny the possibility (though as yet unexplained by an actual appeal to facts) of 

 accounting for this singular collocation by an extremely sharp, inverted curvature, 

 followed of course by powerful denudation. Lastly, I would now observe, that 

 the naturalists who are most ojiposed to the views of MM. De Beaumont and 

 Sismonda have not visited the locality, which they really must do before they cau 

 explain away by fair demonstration what they consider to be an anomaly. 



