288 COSMOS. 



not to be ascribed to these. Fissures, caused by folding in 

 the trachytic mass, which has been elevated while soft and 

 only subsequently hardened, have probably preceded all ac- 

 tions of erosion and the impulse of water. But in those places 

 where deep harrancos appeared in the volcanic districts visit- 

 ed by me on the declivities of bell-shaped or conical mount- 

 ains {en lasfaldas de los Cerros barrancosos), no trace was to 

 be detected of the regularity or radiate ramification with 

 which we are made acquainted by Junghuhn's works in the 

 singular outlines of the volcanoes of Java.* The greatest 

 analogy with the form here referred to is presented by the 

 phenomenon to which Leopold von Buch, and the acute ob- 

 server of volcanoes, Poulet Scrope, have already directed at- 

 tention, namely, that great fissures almost always open at a 

 right or obtuse angle from the centre of the mountain, radi- 

 ating (although undivided) in accordance with the normal 

 direction of the declivities, but not transversely to them. 



The belief in the complete absence of lava streams upon 

 the island of Java,t to which Leopold von Buch appeared to 

 incline in consequence of the observations of Reinwardt, has 

 been rendered more than doubtful by recent observations. 



any chasm. But that the word barranca is connected with barro, clay^ 

 soft, moist loam, and also road-scrapings, is doubtful. 



* Lyell, Manual of Elementary Geology^ 1855, chap, xxix., p. 497. 

 The most remarkable analogy with the phenomenon of regular rib- 

 bing in Java is presented by the surface of the Mantle of the Somma 

 of Vesuvius, upon the seventy folds of which an acute and accurate 

 observer, the astronomer J^us Schmidt, has thrown much light {Die 

 Ervption des Vesuvs im JSm, 1855, s. 101-109). According to Leo- 

 pold von Buch, these valley furrows are not originally rain furrows 

 (fiumare), but consequences of cracking (folding, etoilement) during the 

 first upheaval of the volcano. The usually radial position of the later- 

 al eruptions in relation to the axis of the volcano also appears to be 

 connected therewith (s. 129). 



t "Obsidian, and consequently pumice-stones, are as rare in Java 

 as trachyte itself. Another very curious fact is the absence of any 

 stream of lava in that volcanic island. M. Reinwardt, who has him- 

 self observed a great number of eruptions, says expressly I^Kk there 

 have never been instances of the most violent and destructivc'miption 

 having been accompanied by lavas." — Leopold de Buch, Descr. des 

 Iks Canaries, p. 419. Among the volcanic rocks of Java, for which 

 the Cabinet of Minerals at Berlin is indebted to Dr. Junghuhn, dioritic 

 trachytes are most distinctly recognizable at Burungagung, s. 255 of 

 the Leidner catalogue, at Tjinas, s. 232, and in the Gunung Parang, 

 situated in the district Batu-gangi. This is consequently the identical 

 formation of dioritic trachyte of the volcanoes of Orizaba and Toluca, 

 in Mexico ; of the island Panaria, in the Lipari Islands, and of ^gina, 

 in the ^gean Sea ! 



