4ti0 
VOLCANIC SYSTEMS. 
the volcano of Cotopaxi is a cone, more than one thousand 
eight hundred toises above the basin of Honda, and it 
rises from a table-land, the elevation of which is more than 
one thousand five hundred toises above the valley of the 
Magdalena. In all the colossal mountains of Quito, of the 
province of los Pastos, and of Popayan, crevices and val- 
leys without number intervene. It cannot be admitted, 
under these circumstances, that the noise was transmitted 
through the ah, or over the surface of the globe, and that 
it came from the point at which the cone and crater of 
Cotapaxi are situated. It appears probable, that the more 
elevated part of the kingdom of Quito and the neighbour- 
ing Cordilleras, far from being a group of distinct vol- 
canoes, constitute a single swollen mass, an enormous vol- 
canic wall, stretching from south to north, and the crest 
of which presents a superficies of more than six hundred 
square leagues. Cotopaxi, Tunguragua, Antisana, and Pi- 
chincha, are on this samo raised ground. They have differ- 
ent names, but they are merely separate summits of the 
same volcanic mass. The fire issues sometimes from one, 
sometimes from another of these summits. The obstructed 
craters appear to be extinguished volcanos; but we may 
presume, that, while Cotopaxi or Tunguragua have only one 
or two eruptions in the course of a century, the fire is not 
less continually active under the town of Quito, under 
Pichincha and Imbabura. 
Advancing northward we find, betweeu the volcano of 
Cotopaxi and the town of Honda, two other systems of 
volcanic mountains, those of los Pastos and of Popayan. 
The connection between these systems was manifested in 
the Andes by a phenomenon which I have already had 
occasion to notice, in speaking of the last destruction of 
Cumana. In the month of November 1790 a thick column 
of smoke began to issue from the volcano of Pasto, west of 
the town of that name, and near the valley of Rio Guaytara. 
The mouths of the volcano are lateral, and situated on its 
western declivity, yet during three successive months the 
column of smoke rose so much higher than the ridge of the 
mountain that it was constantly visible to the inhabitants of 
the town of Pasto. They described to us their astonish- 
ment when, on the 4th of February, 1797, they observed the 
