242 Washington — Catalan Volcanoes and their Rocks. 



which runs north and south in the provinces of New Castile 

 and Aragon, and where nephelite-basalts and limburgites are 

 the prominent types.* It must be said, however, that no anal- 

 yses have yet been made of these rocks, so far as I am aware 

 of, so that the question must be left an open one. The matter 

 of the geologic age does not seem to be decisive one way or 

 the other, as the volcanoes of the central line belong to the 

 Tertiary, while there is reason for thinking that the Catalan 

 activity began at about the same time, and also the earliest 

 eruptions at Cabo de Gata antedate the Pliocene. 



Looking north, it would seem to be probable that some of 

 the volcanoes along the southern French littoral, as at Agde 

 and Montpellier, are connected with those of Catalonia. " Ba- 

 salts " are known to occur here, though no analyses of them 

 have yet appeared, to the best of my knowledge. Through 

 the kindness of Prof. Lacroix I have obtained some specimens 

 of these rocks, and hope in the near future to make some anal- 

 yses of them, so as to test this point chemically. 



Chiefly on account of the character of the basalts, and fheir 

 high content in titanium, but on other grounds as well, I have 

 elsewheref expressed the opinion that the Catalan volcanoes 

 are connected genetically with those of Sardinia, Pantelleria, 

 and Linosa, and possibly with eruptions in Tripoli, and even 

 with the volcanoes of the Great Rift Valley in East Africa. 



But the full discussion of the question of this comagmatic 

 region or petrographic province must be postponed until many 

 more analyses are made and the various districts have been 

 described in detail. 



Locust, N. J., May 1, 1907. 



*Calderon, Bol. Soc. Esp. Hist, Nat., p. 336, 1905. 

 fH. S. Washington, Q. J. G. S., vol. lxiii, p. 78, 1907. 



