248 «~DYNAMICAL GEOLOGY. —_‘ [Boor Ill 
succeeded by others when the emissions take place only laterally — 
(ante, p. 214). | Prep 
One consequence of lateral eruption is the formation of minor 
parasitic cones on the flanks of the parent volcano (p. 198). Those 
on Etna, more than 200 in number, are really miniature volcanoes, 
some of them reaching a height of 700 feet. As the lateral vents 
successively become extinct, the cones are buried under sheets of 
















2 3 
Fic. 55.—Mar or Erna, arrer 8. voN WALTERSHAUSEN, 
1, Lava of 1879; 2, Lavas of 1865 and 1852; 3, Lava of 1669; 4, Recent Lavas; 
5, Lavas of the Middle Ages; 6, Ancient Lavas of unknown date; 7, Cones and 
Craters; 8, Non-voleanic Rocks. 
lava and showers of débris thrown out from younger openings or from 
the parent cone. Itsometimes happens that the original funnel is 
disused, and that the eruptions of the volcano take place from a 
newer main vent. Vesuvius, for example (as shown in Fig. 56), 
stands on the site of a portion of the rim of the more ancient and 
much larger vent of Monte Somma. The pretty little example of 
this shifting furnished by Volcancllo has been already noticed (p. 248). 


