﻿The Eruption of Vesuvius. 173 



England, as Mr. Jukes-Browne has remarked, that subdivision of 

 the Chalk almost everywhere ' presents the appearance of having 

 been quietly and continuously accumulated in water that was seldom 

 disturbed by bottom currents,' albeit a tendency to develop hard 

 bands at one horizon, at least, is apparent in the western part of 

 the London Basin. The Phosphatic Chalks of Winterbourne and 

 Taplow evidently mark places on the sea-floor particularly liable to 

 the impingement of strong currents, and may mark places above 

 which the water commonly had a gyratory motion. In any 

 case, their zonal range argues a marked degree of stability in the 

 current-system of the body of water in which they were laid 

 down. 



May 9th. — Aubrey Strahan, M A., F.R.S., Vice-President, 

 in the Chair. 



The following communications were read : — 



1. ' The Eruption of Vesuvius in April 1906.' By Prof. Giuseppe 

 de Lorenzo, For.Corr.G.S. 



After the great eruption of 1872 Vesuvius lapsed into repose, 

 marked by merely solfataric phenomena, for three years. Strom- 

 bolian activity followed, varied by lateral outpourings of lava in 

 1885, 1889, 1891, 1895, etc., and by outbursts from the principal 

 crater in 1900 and 1904. Eissuring of the cone and slight out- 

 pourings of lava began in May 1905, and continued until April 4th, 

 1906, when the first great outburst from the principal crater 

 occurred, accompanied by the formation of deeper and larger fissures 

 in the southern wall of the cone, from which a great mass of fluid 

 and scoriaceous lava was erupted. After a pause the maximum 

 outburst took place during the night of April 7th & 8th, and blew 

 3000 feet into the air scoriae and lapilli of lava, as well as fragments 

 derived from the wreckage of the cone. The south-westerly wind 

 carried this ash to Ottajano and San Giuseppe, which were buried 

 under 3 feet of it, and even swept it on to the Adriatic and Monte- 

 negro. At this time the lava which reached Torre Annunziata was 

 erupted. The decrescent phase began on April 8th, but the collapse 

 of the cone of the principal crater was accompanied by the ejection 

 of steam and dust to a height of from 22,000 to 26,000 feet. On 

 April 9th & 10th the wind was north-easterly, and the dust was 

 carried over Torre del Greco and as far as Spain ; but on April 11th 

 the cloud was again impelled northward. The ash in the earlier 

 eruptions was dark in colour, and made of materials derived directly 

 from the usual type of leucotephritic magma ; but later it became 

 greyer, and mixed with weathered elastic material from the cone. 

 The great cone had an almost horizontal rim on April 13th, very 

 little higher than Monte Somma, and with a crater which possibly 



