246 



MEXICO, CENTRAL AMERICA, WEST INDIES. 



at a little over 6,000 feet, and found the summit pierced by three craters, one of 

 which emitted vapours with hissing and rumbling noises. Izalco is a perfect cone, 

 " as regular as if turned out by a lathe." 



San Salvador, a volcano rising to a height of 6,200 feet, about six miles north 

 of the capital, appears to have been quiescent since pre-Columbian times. From 

 a distance it presents none of the distinctive features of an igneous cone, being an 

 elongated mass with irregular base, and wooded nearly to the summit. But it 

 terminates in the so-called hoqueron, an immense crater nearly round, about three 

 miles in circuit and flooded b}^ a green transparent lake 650 feet deep. On the 

 flanks is an ausol constantly discharging vapours, and near the north base are some 



Fig. 105.— Volcanoes of West Salvador. 

 Scale 1 : 1,200,000. 



69°40 



West oF Greenwich 



18 Miles. 



parasitic cones, one of which, the Quezaltepec volcano, was the scene of a small 

 eruption at the beginning of the century. 



But although the volcanoes in the neighbourhood of the capital have not been 

 the scene of any important eruptions during the historic period, earthquakes have 

 been frequent and almost as disastrous as in any region of the globe. They are 

 all the more dangerous that the ground on which San Salvador is built consists of a 

 whitish tufaceous rock, light and unstable, " floating," so to say, in the depressions 

 of the solid crust without coalescing with it. The city has been overthrown and 

 rebuilt on the same site no less than seven times during the last three centuries. 

 The sudden catastrophe of 1854 swallowed up many victims, while that of 1873 

 was even still more destructive to the buildino's. 



This disturbance appears to have radiated from Lake Ilopango (Apulo), a deep 



