258 
THE MEDITERRANEAN NATURALIST 
Monte Somraa Vesuvius 
Roccamonfiua. 
Monte Vultura. 
Monte Xuovo. 
Phase ? Introductory 
Same. 
Same. 
Introductory explosive 
explosive stage. Pro- 
blematical. 
stage. At fir-:, ejection 
of highly vitreous and 
Phase I. — Chronic acti- 
Same. 
Same. 
microcrystalline (ex- 
cluding platonic - for- 
med minerals) pumice 
followed, 
vity, outflow of leucitic 
Outflow of basalt, 
later by more compact 
basalt, lava, scoria, ash, 
Leucitites 
Haiiyne basalt, and 
and almost continuous 
&c. 
leucitic basalt. 
outflow of Phonolite. 
Phase II. — inactivity, 
Same. 
Same. 
denudation. 
Phase III. — Violent 
Leucoteprites 
Same. 
Same. 
paroxysms, dwindling 
into next phase. 
Production of basalt prr- 
Production of leucitite, 
Production of JEaiiyne 
mice and pumiceous 
pumice and pumiceous 
basalt pumice and pu 
scoria towards the end. 
scoria towards the end. 
miceous scoria toward s 
Phase IV. — Apparent 
Same. 
the end. 
Same. 
return chronic activity. 
(abundant.) 
(Abundant production 
Apparent extinction. 
Leucitic basalt lava 
(small in quantity). 
Phase V. — Inactivity, 
Same. 
of Haiiyne basaitlava.) 
Same. 
denudation. 
Phase VI. — Violent ex- 
Same. 
- 
plosive eruptions. Pro- 
duction of basalt pu- 
mices. 
Phase VII.— -Less vio- 
Production of andesitic 
ions of pumiceons 
scoria, forming the 
present lake basins. ’ 
Haiiyne basalt very 
similar dhvsicallv to 
lent, dwindling into 
next phase. 
ash in enormous quan- 
Phase VII., period 5 of 
titles. 
Vesuvius. 
Production of leucitic 
basalt pumices and pu- 
miceous scorias to- 
wards the end. 
Phase VIII. — Chronic 
activity, outflow of 
leucitic basalt lava. 
Eruption of large quan- 
tities of andesitic lava. 
From this Table we learn that a series of inter- 
missions take place in the 'activity of a volcano ; 
that following these intermissions we have the 
production of fragmentary pumiceous scoria stage 
to that of true lavas. The striking resemblance 
between the phenomena of the three first-named 
volcanoes up to a certain stage cannot but strike 
the observer as very remarkable, and opens a wide 
field of investigation, for it is quite certain that 
similar stages in each of these volcanoes were not 
contemporaneous. 
The igneous magma, whilst confined below may 
have undergone partial crystallization before it 
reaches the surface. In that case, however rapid 
the ejection and cooling be, the ejectamenta will 
always contain those fanned materials, as seems 
to have been the case with sauidiu \ amphibole, 
and, perhaps, other minerals in all the pumices of 
Vesuvius, Mt. Vultura, Roccomontina, the Campi 
Phlegrmi, Ischia, Am. Incase of the magma con- 
taining a large amount of did’used (2) the sudden 
and rapid conversion of this into the gaseous state 
