SOUTH AMERICA. 153 



entirely dry. The number of lakes and basins, great and small, which for- 

 mei'ly covered the elevated plateau of the Andes, must have been very great; 

 but we now find only here and there a small sheet of water. The former 

 lakes are only represented by the more or less extensive pampas, forming 

 basins at great altitudes, showing plainly that the whole of this district is 

 receiving a much smaller waterfell tlian in former times, but probably not in 

 historic times, if we take into consideration the position of some of the most 

 ancient ruins of Bolivia (at Tiahuanaco), which are onlv about seventy-five 

 feet above the present level of the lake." 



The diminution of the water, shown by Mr. Agassiz to be so positively 

 proved for the region embraced within the field of his explorations, did not 

 escape the notice of Humboldt ; on the contrary, he repeatedly calls atten- 

 tion to the foct of a general desiccation in those parts of South America 

 which he visited, and he comments, somewhat at length, on the cause of the 

 phenomenon. The decrease in size of the Lake of Valencia, near Caraccas, 

 especially interested him, as will be evident from the following quotation : 

 " But it is not alone the picturesque beauties of the Lake of Valencia that 

 have given celebrity to its banks. This basin presents several other phenom- 

 ena, and suggests questions, the solution of which is interesting alike to 

 science and to the well-being of the inhabitants. What are the causes of 

 the diminution of the waters of the lake ? Is this diminution more rapid now 

 than in former ages ?....! have no doubt that, in very remote times, the 

 whole valley, from the foot of the mountains of Cocuyza to those of Torito 

 and Nirgua, and from La Sierra de Mariara to the chain of Guigue, of Gua- 



cimo, and La Palma, was filled with water Within half a century, and 



particularly within these thirty years, the natural desiccation of this great 

 basin has excited general attention. We find vast tracts of land which were 

 formerly inundated, now dry, and already cultivated with plantains, sugar- 

 canes, or cotton. Whei-ever a hut is erected on the bank of the lake, we see 

 the shore receding from year to year. We discover islands, which, in con- 

 sequence of the retreat of the waters, are just beginning to be joined to the 

 continent, as for instance the rocky i.sland of Culebra, in the direction of 

 Guigue ; other islands already form promontories, as the Morro, between 

 Guigue and Nueva Valencia, and La Cabrera, southeast of Mariara ; others 

 again are now rising in the islands themselves like scattered hills."* 



Humboldt continues, at length, with the narration of similar facts, proving 



• Personal Narrative of Tr.iTels to the Eciuinoctial Regions of America. Bolin's Ed. in 3 vols. Vol. II. p. 4. 



