Washington — Catalan Volcanoes and their Rocks. 217 



Art. XXIII. — The Catalan Volcanoes and their Rocks ; by 

 Henry S. Washington. 



Introductory. 



The volcanoes in the vicinity of Olot in Catalonia seem to 

 have been first noticed by F. Bolos in 1796,* and later by 

 Maclnre,f and were described in the nineteenth century by 

 several geologists, among whom may be named Lyell % and 

 Carez.§ Within the last few years renewed attention has been 

 directed to these volcanoes by the Spanish Society of Natural 

 History, which appointed a commission to undertake a mono- 

 graphic study of them. A preliminary report of this com- 

 mission appeared in 1904, | and it is expected that the final 

 results of its labors will be published in the near future. The 

 same year also saw the publication of the two latest papers on 

 these volcanoes. The one is a small, illustrated pamphlet by 

 Gelabert,^[ who describes the physical features of the district 

 in a rather popular way, and without any petrographical or 

 chemical discussion. The other is a brief but very instructive 

 sketch of the general volcanological features of the vicinity of 

 Olot by Sapper.** 



While the main physical and geological features are thus 

 well known, the petrographical characters of the rocks have 

 been comparatively neglected. .Recognized in the field by the 

 earlier observers as basalts, they were studied by Quiroga,ff 

 who established the presence of feldspar basalts, nephelite 

 basalts, and limburgites — determinations which my own 

 observations substantiate. Some of Carez's and Sapper's speci- 

 mens were reported to be feldspar basalts, which is a suffi- 

 ciently accurate designation for many of the rocks in the 

 absence of chemical analyses. 



It was to collect material to supply these deficiencies in our 

 knowledge, and especially to undertake the chemical investiga- 

 tion of these presumably interesting rocks, that the writer 

 visited the region in the summer of 1905 with the aid of a 

 grant from the Carnegie Institution of Washington. Head- 



*Cf. L.M.Vidal, Bull. Soc. Geol. Fr., vol. xxvi, 1898, p. 675. 



fCf. C. Daubeny, Description of Volcanoes. London, 1848, p. 295. 



%Q. Lyell, Principles of Geology, 1840, vol. iii, p. 185. 



§ L. Carez, Etude des Terrains Cretaces et Tertiaires du Nord de l'Espagne, 

 Paris, 1881, p. 299. ' 



1 S. Calderon, Bol. Soc. Esp. Hist. Nat., p. 330, 1904. 



if J. Gelabert, Los Volcanes extinguidos de la Provincia de Gerona. San 

 Feliu de Guixols, 1904, 120 pp., small 8vo, with map. 



**K. Sapper, Die Catalonischen Vulkane, Zeits. d. deutsch. geol. Ges., 

 vol. liv, p. 240, 1904. 



ffCf. S. Calderon, Bull. Soc. Geol. Fr. (3), vol. xiv, pp. 13, 114, 1885. 

 Am. Jour. Sci. — Fourth Series, Vol. XXIV, No. 141.— September, 1907. 

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