278 COSMOS. 



pie, at present in the volcano of Izalco ; but the descrip- 

 tions which have been given by eye-witnesses of the lava- 

 producing eruptions of the four volcanoes, Nindiri, el Nuevo, 

 Conseguina, and San Miguel de Bosotlan, give an opposite 

 testimony 68 . 



I have purposely dwelt at length upon the details of the 

 position and close approximation of the linear volcanoes of 

 Central America, in the hope that some day a geogaosist, 

 who has previously given a profound study to the active 

 volcanoes of Europe, and the extinct ones of Auvergne, 

 the Vivarais or the Eifel, and who also (this is of the 

 greatest importance) knows how to describe the mineral- 

 ogical composition of the different rocks in accordance 

 with the present state of our knowledge, may feel himself 

 impelled to visit this region, which is so near and so 

 accessible. Even if the traveller should devote himself 

 exclusively to geognostic investigations, there still remains 

 much to be done here, especially the oryctognostic deter- 

 mination of the trachytic, doleritic, and melaphyric rocks ; 

 the separation of the primitive mass upheaved, and of the 

 portion of the elevated mass which has been covered over 

 by subsequent eruptions ; the seeking out and recognition 

 of true, slender, uninterrupted lava-streams, which are only 

 too frequently confounded with accumulations of erupted 

 scoriae. Conical mountains, which have never been opened, 

 rising in a dome or bell-like form, such as Chimborazo, are 

 therefore to be clearly separated from volcanoes which have 

 been, or still are, active, throwing out scoriae and lava- 

 streams, like Vesuvius and Etna, or scoriae and ashes alone, 

 like Pichincha or Cotopaxi. I know nothing that promises 

 to impart a more brilliant impetus to our knowledge of vol- 

 canic activity, which is still very deficient in multiplicity 

 of observations in large and connected continental districts. 

 As the material results of such a labour, collections of 

 rocks would be brought home from many isolated, true vol- 



68 Compare Squier, Nicaragua, vol. ii, p. 103, with pp. 106 and 111, 

 as also his previous small \vork On the Volcanoes of Central America, 

 1850, p. 7; Leopold de Buch, lies Canaries, p. 506, where reference 

 is made to the lava-stream which broke out of the volcano Nindiri in 

 1775, and which has been recently again seen by a very scientific ob- 

 server, Dr. Oersted, 



