330 Meporfs and Proceedings — Geological Society of London. 



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. Fissuring 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 niglit of April 7th and 8th, and blew 

 3,000 feet into the air scorife 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 and 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 coloui', and made of materials derived directly 

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

 greyer, and mixed with weathered clastic 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 

 exceeds 1,000 feet in diameter; this cone was almost snow-white 

 from the deposit of sublimates. Many deaths were due to asphj'xia, 

 but the collapse of roofs weighted with dust was a source of much 

 danger, as was the case at Pompeii in a.d. 79. The lava-streams 

 surrounded trees, many of which still stood in the hot lava with 

 their leaves and blossoms apparently uninjured. The sea-level 

 during the 7th and Sth of April was lowered 6 inches near Pozzuoli 

 and as much as 12 inches near Portici, and had not returned to its 

 previous level on April 18th. The maximum activity coincided 

 almost exactly with the full moon, and at the time the volcanoes of 

 the Phlegrfean Fields and of the Islands remained in their normal 

 condition. The author believes that this eruption of Vesuvius is 

 greater than any of those recorded in history, with two exceptions — 

 those of A.D. 79 and of 1631. 



2. " The Ordovician Eocks of Western Caermarthenshire." By 

 David Cledlyn Evans, F.G.S. 



The ground dealt with is pi-actically identical with that examined 

 by the late Thomas Koberts, whose notes were published in 1893. 

 It extends from the Kiver Cywyn on the east to the Tave on the 

 west, and from the base of the Old Eed Sandstone on the south to 

 the top of the Dicranograptus Shales on the north. The area is, in 

 the main, a denuded anticlinal fold with an east-and-west axis. 



