458 Reviews — Geology of Guatemala and Salvador. 



them readies nearly 8,500 feet above the sea. In the centre there 

 is a vast semicircular area, evidently the remaining portion of a 

 colossal crater, while two considerable cones, each having a regu- 

 larly circular crater at their summits, stand like sentinels on either 

 horn of the crescent. One of these contains a circular lake. Prom 

 the foot of the other cone an immense lava-stream spreads over a 

 wide area of the high plain around. It was produced by an 

 eruption in 1755. 



From the summit of Pacaya a favourable view is obtained of the 

 volcano d'Agua, a perfectly regular cone, more than 11,000 feet 

 high, from which descended, in 1541, a torrent of water — the con- 

 tents, no doubt, of a crater-lake on the summit, which destroyed the 

 old town of Gruatemala, and occasioned the removal of its in- 

 habitants to a new site. Next to this, and nearly equal in elevation, 

 is the cone called 'di Fuego,' from the heated vapours still evolved 

 from its summit. This cone, perfectly regular on three sides, 

 presents on the fourth what appears to be a portion of a vast 

 breached crater. Another crater, quite circular, and 1,500 feet in 

 depth, exists on the summit, which is nearly 12,000 feet in 

 height. The lavas produced by both these last volcanos seem to be 

 trachytic, though our authors are unwilling to admit that any of the 

 trachytic porphyries which compose the rocks around these craters 

 are true lavas. 



A short distance westwards, a group of three volcanic cones 

 united at their base rise from the southern shore of the lake of 

 Amatitlan (4,560 feet). The largest was eruptive in 1828, 1833, and 

 again in 1852, throwing out vast quantities of ash, with fearful 

 detonations. A great rent in the southern slope of the cone dis- 

 closes its composition of trachytic conglomerate and massive 

 trachyte. The authors seem even here also to doubt that this 

 rock is the product of the volcano itself, though their description 

 and drawings make it difficult to suppose it to have had any other 

 origin. 



Still further westwards, in lat. 14° 50', we come to the volcanic 

 group of Quezaltenango, consisting of two principal cones, the 

 Cerro Quemado, and Santa Maria, the latter dormant (10,500 feet 

 high), the former in eruption in 1785, and still smoking. Its 

 summit is lower by near 2,000 feet than its sister cone, owing 

 apparently to its having been truncated by the last eruption, which 

 has left a wide crater, rather polygonal than circular, partly sur- 

 rounded by abrupt cliffs and peaked eminences composed of trachyte, 

 one side having broken down to give issue to a vast torrent of lava, 

 which adheres to the outside of the cone as a buttress-like mass of 

 great size and height above the neighbouring plain. The surface of 

 this lava mass is covered with blocks and scorified peaks. And our 

 authors appear to feel great difficulty in recognizing it as having 

 flowed as lava out of the crater, not being aware, perhaps, that it is 

 a not unusual characteristic of some lavas, especially those of highly 

 crystalline matter, to possess at their escape from the vent a very 

 low degree of fluidity, and also to split and break up superficially 



