248 



J. W. Judd — On Volcanos. 



and pottery ; (b) is the analysis of the concretionary nodules re- 

 sembling the masses, often septariform, which abound in so many 

 clays and marls ; (c) a similar fine-grained white rock, but contain- 

 ing 1844 per cent, of carbonate of lime ; and (d) the composition 

 of the residue of the same rock after the carbonate of lime, doubtless 

 owing its presence to organic remains, has been removed by acetic 

 acid. 



Fig. 14. — Plan of the Island op Ischia. 



a, a, a, The semi-circular Crater-ring of Epomeo. 



b, c, d, M. Vetta, M. Trippia, and M. Garofali; portions of lavas proceeding from central crater. 

 e i f> ff> h> Plateaux composed of old lavas. 



k, Montagnone 



Products of the most recent eruptions. 



I, Monte Botaro 

 m, Monte Tabor 

 ii, Castiglione 

 o, Lago di Bagno 

 p, The Cremata 

 r, Lava of the Arso ] 

 x, x, x, Baised beaches. 



The mountain of Epomeo or S. Nicola attains a height, according 

 to the measurement of Scacchi, of 2608 feet. The mass of tuffs 

 of which it is composed constitutes a great semi-circular wall 

 surrounding a vast crater (see Plan of the Island, Fig. 14), about 

 two miles in diameter, at the bottom of which are situated the 

 villages of Fontana and Meropano. The depth of this great 

 crater, of which the walls unsustained by the binding courses 

 constituted by lava-streams, or the buttresses formed by dykes, are 

 in a state of great ruin from denudation, is about 2000 feet. At 

 its eastern extremity the great wall bounding the crater on its 

 northern side is 2215 feet above the sea, and several of its highest 

 peaks are in this part over 2500 feet ; on the west and south-west 

 this crater-wall is found to gradually decline in elevation, until 

 above Serrara it is only 1276 feet. On its south, south-east, and 

 eastern sides the crater-rim has been almost completely destroyed, 

 owing to causes which will be presently noticed. 



On its outer slopes the great cone of Epomeo is made 

 up of fine-grained, well- stratified tuffs, dipping outwardly from the 

 centre, and alternating with beds of so-called clay, marl and chalky- 



