214 MEXICO, CENTRAL AMERICA, WEST INDIES. 



shifted by the tides and tempests. One of the largest streams on the Pacific side 

 is the Suchiate, which forms the common frontier between Guatemala and Mexico, 

 A still more extensive basin is that of the Samala, which flows from the Quezal- 

 tenango and Totonicapam heights. The Iztacapa is a smaller river, although it 

 receives the overflow of Lake Atitlan, not through a surface stream, but through 

 underground filtrations across the scoriae covering the plain of San Lucas, on the 

 southern bank. Lake Atitlan itself, which has an area of 6Ô square miles, 

 develops an irregular crescent at an altitude of 5,140 feet, round the spurs of the 

 Atitlan volcano, which rises on its southern margin, and which created the lake by 

 damming up the fluvial valleys. The waters thus pent up by the accumulating beds 

 of ashes and lavas gradually filled the vast Atitlan basin, which is said to have a 

 depth of over 1,650 feet. The water, being continually renewed, thanks to the 

 subterranean outflow, is perfectly fresh and limpid. 



Farther east the smaller Lake Amatitlan has been formed under analogous 

 conditions at an altitude of 4,000 feet. Here the waters have been gradually 

 dammed up by the lavas and scoriae deposited by the Pacaya volcano on the south 

 side of the lake. Formerly its basin was even far more extensive than at present, 

 and traces of its old level are still distinctly visible at distances of several miles 

 from the present margin. The water of Amatitlan, which exceeds 200 fathoms in 

 depth, is as fresh as, but less pure than, that of Atitlan, and along the margin its 

 temperature is raised by thermal springs. Nearly two hundred years ago Thomas 

 Gage spoke of it as " somewhat brackish," adding that salt was collected on its 

 shores. Such is no longer the case, its flavour being in no way affected by the 

 slightly purgative salts of soda and magnesia which it contains in solution, though 

 they give rise to a strong odour during the dry season. It is probably fed by 

 underground affluents, the few surface streams draining to the basin being 

 insuflicient to create an emissary. The overflow is discharged south-eastwards to 

 the Michatoya, or " Fish River," which escapes from the plateau through a deep 

 gorge 600 or 700 feet below an escarpment of the Pacaya volcano. Farther on 

 the affluent has a clear fall of 200 feet near San Pedro Martir, beyond which 

 point it loses itself in the coast lagoons a little to the east of the port of San José. 



Amatitlan lies about midway between Atitlan and Ayarza (Ayarces), a third 

 flooded depression at the southern foot of the Mataquezcuintla mountains, which 

 here rise to a height of over 8,000 feet. But Ayarza already belongs to the San 

 Salvador hydrographie system, draining through the Ostua to the fluvial basin of 

 the Rio Lempa, main artery of the neighbouring state. On the Atlantic slope, 

 also all the M'estern and northern regions, at least one -half of the whole territory 

 belongs to the Usumacinta basin, which throughout its lower course flows through 

 Mexican territory. The largest watercourse entirely comprised within the limits 

 of Guatemala is the Motagua, which, like so many others in Spanish America, is 

 called also the Rio Grande. It rises in the central mass of the Altos de Totoni- 

 capam, where its headstreams are intermingled with those of the Usumacinta. 

 Farther east it collects all the torrents descending from the main Guatemalan 

 waterparting, which in many places is contracted to a narrow ridge furrowed on 



