344 THE ROMAN CAMPAGNA 



since entered into the closing or Solfatara stage, when 

 only steam, hot vapours, and gases are emitted. But 

 at the southern end of the chain lies the still vigorous 

 Solfatara of Naples, with the various cones around it, 

 some of which have been in eruption within the last 

 few centuries, while Vesuvius continues to maintain a 

 persistent though variable activity. Still farther south 

 lie the ^Eolian Islands, where Volcano occasionally breaks 

 out, while Stromboli remains, as it has done since the 

 beginning of authentic history, in a state of constant 

 ebullition and eructation. At the far extremity of 

 the volcanic belt rises the colossal cone of Etna, which 

 from time to time displays an energy worthy of its 

 place among the great volcanoes of the globe. 



III. We have traced how the platform of the 

 Campagna has been step by step built up, partly by 

 the accumulation of silt, sand, and gravel on the sea- 

 floor, partly by submarine volcanic ejections, and partly 

 by a widespread uplift of the whole region above sea- 

 level, and by continued subaerial volcanic activity. We 

 now reach the third and last section of our history 

 in which we have to consider how the present topo- 

 graphy of the ground has been produced. A little 

 reflection will convince us that, even before its elevation 

 into land, the submerged surface of the district was 

 probably far from presenting a dead flat, though it 

 no doubt approached nearer to that form than it has 

 ever done since. In spite of the levelling action of 

 waves and currents, the sea-floor in front of the 

 Apennine chain must have abounded in inequalities 

 caused not only by the scour of the water, but more 

 especially by the irregular distribution of the volcanic 



