ixxxii PROCEEDtNGS OF THE GEOLOGICAL SOCIETY, 



should hitherto have been so httle an object of attention, in a country 

 so frequented, on the very borders of the Phlegrsean Fields, visited 

 and described by so many geologists. Breislak, in his * Voyages 

 Physiques et Lithologiques dans la Campanie,' published in 1801, 

 refers to it cursorily, but does not appear to have examined it with 

 any care ; Dr. Daubeny himself, in his general work on volcanos, 

 published in 1826, gives only a general outline of its structure in 

 half a page ; Mr. Lyell in his account of the volcanic district of 

 Naples makes no mention of it* ; neither does Friedrich Hoffman 

 in 1832f, nor M. Dufrenoy in his ' Memoire sur les Terrains Vol- 

 caniques des environs de Naples,' published in 1838. M. Abich 

 appears to have been the first geologist who had examined Rocca 

 Monfina with care ; he spent three weeks in the investigation of it 

 in 1838, and has given an account of it in his work published in the 

 autumn of 1841, 'Ueber die Natur und den Zusammenhang dervul- 

 kanischen Bildungen,' which, though brief, is accompanied by two ex- 

 cellent maps. He tells us thatM. Pillaof Naples, having seen his map, 

 subsequently examined the mountain ; and there is in the eighteenth 

 volume of the ' Annales des Mines,' which appeared in the spring of 

 1841, an account of Rocca Monfina by M. Pilla ; without however any 

 mention of the labours of M. Abich, who had preceded him. 



This mountain lies about 30 miles N.W. of Naples, immediately 

 above the toT^Tis of Teano and Sessa, the river Garigliano washing its 

 base. The summit of the conical hill that rises from the centre of 

 the crater, called the Monte de Santa-Croce, was the stronghold of 

 the Aurunci, who successfully resisted the power of Rome until a.u.c. 

 410. As vestiges of the ruined city are still to be seen, and as the 

 Aurunci are mentioned at a very early period in Roman history, it is 

 clear that there has been no eruption for at least 2500 years. The 

 interior of the crater is covered with a fertile soil and clothed with 

 vegetation, as is the central cone ; and Dr. Daubeny tells us that the 

 late Sir W. Gell observed to him, that "a nation like the Aurunci, 

 to whom it was of essential importance to have near their city good 

 pasturage for the flocks and herds, on which they depended for 

 support, would never have selected Rocca Monfina for their capital, 

 not only if the volcano itself had been in activity, but had not the 

 stone which constitutes the interior of the crater been already in such 

 a state of decomposition as to be covered with herbage, and to yield 

 abundant crops." We have no means of estimating the period when 

 the volcano was in activity, but this we know, that the mountain must 

 have been formed by a sub-aerial eruption, that it has never since been 

 submerged, and therefore that its age is posterior to that very modern 

 period in geological chronology when the species of moUusca now found 

 in the neighbouring sea were in existence, and when the country was 

 inhabited by the elephants whose remains are met with in the super- 

 ficial soil. 



This volcanic group is continuous with, or rather included in, an 

 oifset of the Apennines, the celebrated Mons Massicus, composed of 



* Principles of Geology, ii- ch. 11, 12. 



t Geognostische Beobachtungen, published in 1839. 



