402 VIEWS OF NATURE. 



called the Pongo de Manseriche, between Santiago and 

 San Borja, the breadth is less than 160 feet. The Pongo 

 de Manseriche is formed by a mountain ravine, in some 

 parts of which the overhanging rocks, roofed by a canopy 

 of foliage, permit only a feeble light to penetrate, and by 

 the force of the current all the drift-wood, consisting of 

 trunks of trees in countless numbers, is broken and dashed 

 to atoms. The rocks by which all these Pongos are formed, 

 have, in the course of centuries, undergone many changes. 

 The Pongo de Rentema, which I have mentioned above, 

 was, a year before my visit to it, in part broken up by a 

 high flood; indeed the inhabitants of the shores of the 

 Amazon still preserve by tradition a lively recollection of the 

 sudden fall of the once lofty masses of rock along the whole 

 length of the Pongo. This fall took place in the early part 

 of the last century, and the debris suddenly dammed up the 

 river and impeded the current. The consequence was, that 

 the inhabitants of the village of Puyaya, situated at the lower 

 part of the Pongo de Rentema, were filled with alarm on 

 beholding the dry bed of the river ; but, after the lapse of a 

 few hours, the waters recovered their usual course. There 

 appears to be no reason for believing that these remarkable 

 phenomena are occasioned by earthquakes. The river, which 

 has a very strong current, seems, as it were, to be incessantly 

 labouring to improve its bed. Of the force of its efforts some 

 idea may be formed from the fact that, notwithstanding its 

 vast breadth, it sometimes rises upwards of 26 feet above its 

 ordinary level in the space of 20 or 30 hours. 



We remained seventeen days in the hot valley of the Maranon 

 •or the Amazon River. To proceed from thence to the coast 

 of the Pacific it is necessarv to cross the chain of the Andes, 

 between Micuipampa and Caxamarca (in 6° 57' S. lat., and 

 78° 34' W. long.), at a point where, according to my observa- 

 tions, it is intersected by the magnetic equator. At a still 

 higher elevation are situated the celebrated silver mines of 



