Yol. 6$.^ BASALTS OF THE WESTERN MEDITERRANEAN. 79 



Islands, the neighbourhood of Cartagena, Cabo de Gata, and Alboran 

 Island. But their rocks demand further chemical investigation, 

 the earlier analyses either neglecting the titanium or giving rise to 

 uneasiness on the score of accuracy. In a recent highly-interesting 

 paper x Dr. A. Osann has described the rocks of two localities in 

 Murcia, and his description is accompanied by careful and complete 

 analyses by Dittrich. These do not show the high amounts of 

 titanium which we might expect if the rocks belong to the same 

 region as that dealt with here, although they are somewhat higher 

 than the average in this constituent. 



A possible extension southward from Linosa is indicated by the 

 occurrence of a phonolite at Msid Gharian, near Tripoli, described 

 by Prof. L. van Werveke. 2 The possible connexion of the rocks 

 of Pantelleria with those of Abyssinia and the Great Eift Yalley in 

 East Africa, has already been suggested by Dr. G. T. Prior. 3 



Discussion. 



The President expressed the gratification with which the Society 

 received this paper, as a recognition from the Author of his election 

 as one of the Society's Corresponding Fellows. The paper was an 

 extension of the work which, for some j'ears past, the Author had 

 been carrying on in the basin of the Mediterranean. It showed 

 the same firm grasp of petrographical methods, the same reliance on 

 minute and accurate chemical analysis, and the same successful 

 €o-ordination of facts in the natural history of rock-groups. The 

 high percentage of titanium in the rocks now described was a point 

 of considerable interest and importance, and seemed to justify the 

 Author's separation of the region of the Western Mediterranean as 

 a distinct petrographical province, so far at least as regards its later 

 basaltic eruptions. 



Dr. Teall agreed with the President in his estimate of the value 

 of the paper, which dealt with a very interesting and somewhat 

 peculiar group of rocks. The Author had done much to give 

 definiteness and precision to our chemical knowledge of igneous 

 rocks, and he (the speaker) felt sure that all the Fellows would 

 welcome this communication. 



Dr. J. W. Evans thought that the paper emphasized the import- 

 ance of exact and complete analytical work, especially in connexion 

 with the minor chemical constituents. He had had the oppor- 

 tunity of examining numerous concentrates of the heavy minerals 

 of sands, and was struck by the prominent place taken by ilmenite 

 and other titanium-bearing minerals. He also drew attention to 

 the large percentage of titanium-oxide which is often present in 

 bauxite, usually a product of the decomposition of igneous rocks; 

 and expressed his belief that many other occurrences of rocks rich 

 in titanium would be discovered. 



1 'Ueber einige Alkaligesteine aus Spanien' Rosenbusch Festschrift, 1906, 

 p. 263. 



2 L. van Werveke, Neues Jahrb. vol. ii (1880) p. 275. 



3 Min. Mag. vol. xiii (1903) p. 228. 



