524 



PROCEEDINGS OP THE GEOLOGICAL SOCIETY. [Feb. 2, 



The broken edge of the new crater's rim showed, still smoking, 

 sections of the lava- currents which, for some years, I myself had 

 watched successively flowing down the sides of the cone from minor 

 eruptions at its summit, and leaving soHd ribs of lava- rock upon its 

 surface-slopes, up which ribs I often cHmbed the cone. I had, 

 through the same period, seen an abundance of fragmentary lava and 

 scoriae discharged from various upper mouths, forming hillocks and 

 protuberances upon the rude platform which then surmounted the 

 cone ; one of which minor cones, measuring no less than 450 ft. in 

 height, was thrown up within three months in the early part of that 

 year (1822), a fact confirmed by the testimony of MM. Monticelli and 

 Covelli. And with this positive experience of the rapid growth under 

 my own eyes of the cone of Vesuvius within two or three years only 

 of comparatively moderate activity, and with the knowledge derived 

 from authentic records of some fifty or more paroxysmal eruptions, 

 many of them of greater violence, having occurred from this same 

 volcanic vent during the last eighteen centuries, can I entertain any 

 respect for a theory which tells me that the entire mountain was 

 formed, just as we now see it, in the year 79, by some unintelligible, 

 or at least unexampled, process — that it has not since that epoch 

 grown at all by the accumulation of the erupted matters, whether 

 lavas or scoriae — ^nay, that it has rather diminished than increased in 

 bulk and height from the time of its original inflation ? Eor that is the 

 assertion put forth by de Buch, and endorsed by M. de Humboldt ! 

 Have we not also a right to ask those who refuse to believe the still 

 larger volcanic mountains of either hemisphere to be built up from 

 the accumulated lavas and fragmentary ejections of their repeated 

 eruptions, what else can have become of all these erupted matters ? 

 Many such volcanos are known to have been in frequent or habitual 

 eruption during even recent historical times, ejecting vast quantities 

 of scoriae, pumice, and ashes, and enormous streams of lava from 

 their central crater or its immediate vicinity. It is fairly pre- 

 sumable that for long previous ages similar eruptions had been taking 



Eig. 9. — Ideal section of a Volcanic Cone, formed of the products of 



repeated Eruptions. 



place from the same vents. The eruptionists admit that a single 

 eruption will give birth (by accumulation, not upheaval) to a hill of 



