RIVERS OF SALVADOR. 249 



to its isolation, its rugged slopes, and sharply-truncated upper crest, presents an 

 aspect of unrivalled grandeur, offers a superb prospect of the surrounding plains 

 and river valleys away to the Pacific and ramifying inlets of Fonseca Bay. San 

 Miguel has been in eruption several times during the historic period, and in 1844 

 as many as fourteen fissures on its flanks discharged diverging streams of lava, one 

 of which flowed ten miles northwards to the outskirts of the city of San Miguel. 

 The terminal crater is one of the largest in Central America, being nearly two 

 miles in circuit and 500 feet deep. 



Farther east the volcanic chain terminates in the twin crested Conchagua, 

 whose gently-inclined wooded slopes project into Fonseca Bay. Conchagua, whose 

 chief summit, the Cerro del Ocote, rises to a height of 4,100 feet, was supposed to 

 be extinct till the year 18ti8, when a fissure was opened on its flanks, whence 

 issued dense volumes of vapours, accompanied by violent earthquakes and avalanches 

 of rocks. 



The lava streams which have been discharged parallel with the Pacific coast 

 have certainly contributed to modify the hydrographie system of Salvador by 

 damming up the streams and compelling them either to excavate fresh channels or 

 to fill vast lacustrine depressions. A distinct waterparting has been formed by 

 the volcanic range, whence on one side flow rapid torrents seawards, while, on the 

 other, the running waters converge in the great valley of the Rio Lempa, running 

 parallel with the igneous axis and the main Honduras range. 



The LemjDa, one of the chief rivers of Central America, rises in Guatemala, one 

 of its headstreams descending from the famous shrine of Esquipulas. After 

 crossing the frontier it receives the overflow of the great Lake Guija, which is 

 itself fed by the Ostua and numerous torrents from the surrounding mountains. 



Below the confluence the LemjDa continues to flow parallel with the Pacific 

 coast, receiving on both banks numerous tributaries from the northern and southern 

 ranges. Beyond its junction with its largest affluent, the Sumpul from the 

 Honduras mountains, it is joined from the east by the Tonola. Be^^ond this point 

 the mainstream forces a passage through the escarpments of the plateau down to 

 the plains, where its yellow waters, scarcely 10 feet deep in the dry se;)son, flow 

 with a sluggish current a few yards above the level of the Pacific. During the 

 floods its lower course has a depth of from 20 to 26 feet, but at its mouth it is 

 obstructed by a bar never more than six or seven feet deep. Thus the Lempa, with 

 a course of about 185 miles, a catchment basin 6,000 square miles in extent, and a 

 mean discharge of from 16,000 to 24,000 cubic feet per second, is inaccessible to 

 marine navigation, though river steamers can ascend its lower reaches to the 

 great southern bend at the Tonola confluence. The San Miguel, which flows in a 

 nearly parallel channel farther east, enters the sea at the Estero de Jiquilisco, an 

 inlet which might easily be connected with the Lempa. 



The Salvador coast, like that of Guatemala, has been subject to numerous 

 changes of level in past times. Banks of recent shells lying some distance inland 

 show that the beach has been upheaved, or else that the neighbouring waters have 

 subsided. 



