266 COSMOS. 



south-southeast to north-northwest almost at right angles, are 

 geological phenomena no less important than the distance of 

 the eruption of Jorullo from he seas, the evidence of its up- 

 heaval which I have represented graphically in detail, the 

 innumerable fuming hornitos which surround the volcano, 

 and the fragments of granite, which I found immersed in 

 the lava poaired forth from the principal volcano of Jorullo, 

 in a district which is destitute of granite for a long distance. 

 The following table contains the special local determina- 

 tions and elevations of th* series of volcanoes of Anahuac, 

 upon a fissure which, running from sea to sea, intersects the 

 fissure of elevation of the great range of mountains : 



The prolongation of the parallel of volcanic activity in the 

 tropical zone of Mexico leads, at a distance of 506 miles west- 

 ward, from the shores of the Pacific to the insular group Re- 

 villagigedo, in the vicinity of which Collnet saw pumice-stone 

 floating, and perhaps still farther on, at a distance of 3360 ge- 

 ographical miles, to the great volcano Mauna Roa (19 28'), 

 without causing any upheaval of islands in the intervening 

 space ! 



The group of linear volcanoes of Quito and New Granada 

 includes a volcanic zone which extends from 2 S. lat. to 

 nearly 5 N. lat. The extreme boundaries of the area in 

 which the reaction of the interior of the earth upon its surface 

 is now manifested are the uninterruptedly active Sangay, and 

 the Paramo and Volcan de Ruiz, the most recent conflagra- 

 tion of which was in the year 1829, and which was seen smok- 

 ing by Carl Degenhardt from the Mina de Santana, in the 

 province of Mariquita, in 1831, and from Marmato in 1833. 

 The most remarkable traces of great eruptive phenomena next 

 to the Ruiz are exhibited from north to south, by the trun- 

 cated cone of the volcano of Tolima (18,129 feet), celebrated 

 by the recollection of the destructive eruption of the 12th 

 March, 1595 ; the volcanoes of Purace (17,006 feet) and So- 

 tara, near Popayan ; that of Pasto (13,450 feet), near the city 

 of the same name ; of the Monte de Azufre (12,821 feet), 



