ITALIAN PETROLOGICAL SKETCHES 243 



described the eruptions date from the Pliocene. The date of 

 extinction of the volcano is likewise uncertain, though probably 

 quite recent. Some lead objects and ancient buildings, with 

 frescoes have been found beneath the tuffs, and the date 269 B.C. 

 has been proposed for this period — on what authority I am unable 

 to state as Moderni's reference is inaccessible to me. Moderni 

 however, taking into consideration the silence of the ancient 

 writers, the want of exact data, and the liability of objects being 

 buried by the easily transported tuff, rejects this view and leaves 

 the question an open one.' The hot springs of Sujo '^ are the 

 last S3'mptoms of volcanic activity manifest at the present day. 



Petrography. — Moderni recognizes three phases of activity in 

 the volcano, distinguished by different products of eruption: (i) 

 the leucitic, the oldest, which is subdivided into two sub-phases 

 characterized by leucitites and leucite-tephrites ; ( 2 ) the trachy tic ; 

 (3) the basaltic, which is the youngest. As my own observa- 

 tions were not extended enough to enable me to judge of this 

 point for myself I shall accept Moderni's views. The volcano is 

 thus seen to form a notable exception to most of the composite 

 volcanoes of Italy — the order of succession of the leucitic and 

 non-leucitic rocks being reversed. Before entering on the petro- 

 graphical descriptions it will be as well to give a brief resume of 

 Moderni's work. 



While it is difficult to unravel certain portions of the history 

 of the volcano one fact is certain, that the first lava erupted was 

 leucitite. This is shown by the fact that it is found beneath all 

 the others. The flows of this rock are the greatest in amount of 

 any of those of the region. They form a large part of the ridge 

 of Mte. Cortinelli, with flows at many points elsewhere round the 

 crater ring which it is unnecessary to enumerate here. There are 

 certain eruptive centers on "^^ - flanks of the volcano which gave 

 vent to this type of rock, but ix. j.st flows of the western half 

 seem to have been poured out of the central crater. Lying above 



' This is also tlie conclusion to which Daubeny comes in the second edition of his 

 Volcanoes, London, 1848, p. 178. 



- Johnston-Lavis, South Italian Volcanoes, Naples, 1891, 73. 



