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Villa de Cura we descended toward the banks 

 of the Rio Tucutunemo, which has hollowed 

 itself out in a serpentine rock a longitudinal 

 valley directed from East to West, at nearly the 

 same level as La Victoria. A transverse valley, 

 lying generally North and South, led us thence 

 into- the Llanos, by the villages of Parapara and 

 Ortiz. It grows very narrow in several parts. 

 Basins, the bottom of which is perfectly hori- 

 zontal, communicate together by narrow passes 

 with steep declivities. They were no doubt 

 formerly small lakes, which by the accumulation 

 of the waters, or by some more violent catas- 

 trophe, broke down the dykes, by which they 

 were separated. This phenomenon is found in 

 both continents, wherever the longitudinal val- 

 leys are examined, that form the passages of 

 the Andes, the Alps % or the Pyrennees. It is 

 probable, that the irruption of the waters toward 

 the Llanos have given by extraordinary rents 

 the form of ruins to the Morros of San Juan and 

 of San Sebastian. The volcanic tract of Para- 

 para and Ortiz is now only 30 or 40 toises above 

 the Llanos. The eruptions consequently took 

 place at the lowest point of the granitic chain. 



In the Mesa de Paja, in the 9th degree of 

 latitude, we entered the basin of the Llanos. The 



* I remind travellers of the road from tlie valley of Ursern 

 to the hospice of St. Gothard, and thence to Airolo. 



u 2 



