Site of the Ancient City of the Aurunci. 215 



unimpaired the fomi as well as the structure of those por- 

 tions of the earth's surface which have been once the theatre 

 of igneous operations ; the medium of communication, as it 

 were, between the atmosphere and the interior of the globe. 



Yet no manifestations of activity are recorded as having 

 been exhibited by it during those periods of Roman history 

 when such phenomena would have excited attention. 



On the contrary, it appears, from the testimony of Horace, 

 to have presented then the same luxuriant vegetation, the 

 same wooded slopes, which we observe at present ; so that 

 the inference seems inevitable, that the grand display of vol- 

 canic activity, which must have accompanied the formation 

 of so considerable a mountain, was limited to a period long 

 anterior to the existence of historical records. 



Of this locality, as well as of the allied phenomena exhi- 

 bited in a spot on the Apennines intermediate between it 

 and Mount Vesuvius, and in a line parallel with both, called 

 of old the Lake Amsanctus, where, just as was the case nearly 

 2000 years ago, in the time of Virgil, copious volumes of 

 carbonic acid gas are constantly given off into the atmo- 

 sphere from some internal focus of volcanic operations, I gave 

 an account on my return at one of the meetings of this So- 

 ciety, and the particulars are contained in a brief memoir 

 since published in our Transactions.* 



One other volcano, however, or rather, I should say, ano- 

 ther distinct system of volcanic operations existing within 

 the Neapolitan territory, remained to be explored ; I mean 

 that of Rocca Monfina, near Sessa, at a distance of about 30 

 miles to the north of Naples. 



This mountain, accordingly, it was my particular object, in 

 the third and last journey I undertook to the south of Italy^ 

 to investigate ; and as it proved in some respects more inter- 

 esting, and more instructive, even than any of those which I 

 .had previously examined, I conceive that a brief account of 

 it will form a suitable appendix to the reports on volcanic 



* Narrative of an Excursion to the Lake Amsanctus and to Mount Vultor 

 in Apulia, 1835, published by the Ashmolean Society. 



