Kerguelen Island is of undoubted volcanic origin, the prevailing rock being basaltic lavas, intersected occasionally by dikes, and an active volcano and hot springs are said to exist in the south-west of the island.
The city is so situated as to be affected by shocks from all the various seismological centres of Luzon, especially those from the active volcano Taal, 35 m.
It is an active volcano with a large flooded caldera open to the sea, which forms a natural harbor.
The only plain of any great extent is that of Catania, watered by the Simeto, in the east; to the north of this plain the active volcano of Etna rises with an exceedingly gentle slope to the height of 10,868 ft.
Sincholagua and Ruminagui are the next two peaks, going southward, and then the unrivalled cone of Cotopaxi - the highest active volcano in the world - from whose summit smoke curls upward unceasingly.
