270 REACTION OF THE INTERIOR OF THE EARTH 



Ruiz, which became again active in 1829, and from 

 which Carl Degenhardt saw smoke issue in 1831 and 

 1833, he being, on the first occasion, at the Mina de 

 Santana in the province of Mariquita, and on the 

 second at Mormato. Proceeding southwards from Ruiz, 

 the next most remarkable traces of great phenomena 

 of eruption are shown by the truncated cone of the 

 volcano of Tolima (18,120 feet), celebrated on account 

 of its devastating eruption of the 12th of March 1595; 

 the volcanoes of Purace (17,006 feet) and Sotara, near 

 Popayan; of Pasto (13,450 feet), near the town of the 

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

 Tuquerres; of Cumbal (15,618 feet); and of Chiles in 

 the Provincia de los Pastos. Then follow the historically 

 more celebrated volcanoes of what is more strictly called 

 the Highland of Quito, south of the equator, of which 

 four, viz. Pichincha, Cotopaxi, Tungurahua, and Sangay, 

 may certainly be regarded as still active. If, as will 

 be presently more fully shown, to the north of the 

 mountain-knot of Robles, near Popayan, where the 

 great chain of the Andes forks into three, it is only in 

 the middle cordillera, and not in the western one which 

 is nearest to the sea, that volcanic activity shows itself, 

 on the other hand, to the south of the said knot, where 

 the Andes form only two parallel chains, being those 

 so often mentioned in the writings of Bouguer and La 

 Condamine, the distribution is so equal that the four 

 volcanoes of Pastos, as well as Cotocachi, Pichincha, 

 Iliniza, Carguairare, and Yana-Urcu at the foot of 

 Chimborazo, have broken forth on the western cordil- 

 lera; and Imbabura, Cayambe, Antisana, Cotopaxi, 

 Tungurahua (over against Chimborazo, yet near the 



