TRUE VOLCANOES. 



281 



The prolongation of the parallel of volcanic activity in 

 the tropical zone of Mexico, leads, at a distance of 506 

 miles westward from the shores of the Pacific to the insular 

 group Revillagigedo, in the vicinity of which Collnet saw 

 pumice-stone floating, and perhaps still farther on, at a dis- 

 tance of 3360 geog. 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 sur- 

 face is now manifested, are the uninterruptedly active San- 

 gay, and the Paramo and Volcan de Ruiz, the most recent 

 conflagration of which was in the year 1829, and which was 

 seen smoking by Carl Degenhardt from the Mina de San- 

 tana in the province of Mariquita in 1831 and from Mar- 

 mato in 1833. The most remarkable traces of great erup- 

 tive phenomena next to the Ruiz, are exhibited from north 

 to south, by the truncated cone of the volcano of Tolima 

 (18,129 feet), celebrated by the recollection of the destruc- 

 tive eruption of the 12th March, 1595 ; the volcanoes of 

 Purace" (17,006 feet) and Sotara near Popayan ; that of 

 Pasto (13,450 feet), near the city of the same name; of 

 the Monte de Azufre (12,821 feet), near Tuquerres ; of 

 Cumbal (15,618 feet), and of Chiles, in the province do los 

 Pastos ; then follow the historically celebrated volcanoes of 

 the true high land of Quito, to the south of the equator, of 

 which four, namely, Pichincha, Cotopaxi, Tungu rah.ua, and 



