316 Geological Society, 



GEOLOGICAL SOCIETY. 



February 25. — A paper was first read, r# On the Volcanic Strata 

 exposed by a Section made on the site of the new Thermal Spring 

 discovered near the town of Torre del Annunziata, in the Bay of 

 Naples j with some remarks on the Gases evolved by this and other 

 Springs connected with the Volcanos of Campania;" by Professor 

 Daubeny, M.D., F.G.S., &c. 



The discovery of a spring near Torre del Annunziata having oc- 

 casioned the removal of a considerable portion of a cliff, a clear sec- 

 tion has been exposed of the volcanic strata constituting that part of 

 the base of Vesuvius. The entire height of the cliff is 68 feet, and it 

 presents the following details : 



Vegetable mould, mixed with decomposed lava, 5 to 10 feet. 



Hard, compact, cellular lava, with occasionally considerable cavi- 

 ties, and scoriform at the bottom, 5 feet. 



In one of the cavities of this stratum, Dr. Daubeny states, on the 

 authority of Colonel Robinson, that a considerable quantity of car- 

 bonate of magnesia was found : and Dr. Daubeny also found in the 

 same lava a white coating, which appeared to contain a very large 

 proportion of it. The author further states that Colonel Robinson has 

 since informed him, that in endeavouring to find the origin of the 

 magnesia, he had excavated to the depth of 40 feet, two miles up 

 Vesuvius, in the direction of the spring, and had found large pieces 

 of pumice, the cavities of which were completely filled with carbonate 

 of magnesia. 



Under the bed of lava, the cliff is principally composed of strata of 

 rapilli and scoriae, of various shades of red, grey, and black, some- 

 times agglutinated by volcanic sand. In the upper portion the beds 

 are blended together, but in the lower they are, for the greater part, 

 tolerably distinct. In the midst of these strata is an irregular bed of 

 compact tuff, terminating abruptly at each extremity ; and at a lower 

 level are one or two other beds of similarly constituted tuff, but trace- 

 able only for a few feet. These beds of tuff, Dr. Daubeny is of opi- 

 nion, were formed on dry land, by rain or torrents, as eight or nine 

 feet lower in the cliff, is an admixture of vegetable mould containing 

 stems of reeds, similar to those now growing in the neighbourhood ; 

 and about one foot still lower are the roots and part of the trunk of 

 a fir, in an upright position, in the soil in which the tree must have 

 grown. Intermixed with the earth, found at this level, fragments of 

 tiles, a piece of hewn timber, and other traces of human art are said 

 to have been discovered ; and at a somewhat higher level, a cypress, 

 also in an upright position. In driving a horizontal gallery, at a 

 level nearly 10 feet below that of the fir, vestiges of walls and 

 buildings with fresco paintings, as well as fragments of Roman pot- 

 tery, and a considerable quantity of cut marble, were discovered, 

 proving the overwhelming, if not of another town, of at least several 

 buildings, by an eruption of Vesuvius. The position of these build- 

 ings corresponds with that of a place mentioned under the name of 

 Oplonti in the Tabula Theodosia?ia, and it is remarkable that the 



