LAKE TITICACA 147 



the total number of species, which is remarkably small 

 for such a large body of water. He also made an ex- 

 cellent collection of Reptiles, found a gigantic Frog, 

 dredo-ed from the shores. Fro^s and Toads are most 

 abundant in the region of the Lake. 



I myself made two trips on the Lake in the small 

 steamers which are run by the Peruvian Government 

 between Peru and Bolivia. During the trips I devoted 

 myself mainly to sounding and to collecting what few 

 antiquities I could pick up at the different ports. The 

 Lake is found extremely deep ; the northeastern shore 

 end is in some places no less than 151 fathoms deep; 

 and in a section from Vilquechico to Puno the depth 

 of the Lake passed gradually from 135 fathoms to about 

 111 fathoms within a short distance of the entrance to 

 Puno Bay; the lake bottom seems made up of a series 

 of long flat plains nearly horizontal and run parallel 

 running northwesterly, separated by the anticlinals which 

 form the ranges of plains found in the lake. 



But a very remarkable feature of the Lake is the 

 temperature of the water; the surface water has an 

 average temperature of about 57°, while the bottom has 

 an invariable temperature at this season of no less than 

 55° to 58° ; even at 151 fathoms the deep-sea thermome- 

 ter stood at 55° ! which for the greater part of the time 

 was greater than the temperature of the air. This con- 

 dition of things is very readily explained from the power- 

 ful action of the nearly vertical sun at this season. The 

 water of course absorbing the heat, retaining it, and 

 becoming an immense caldron of warm water in spite 

 of the large amount of cold water which at this season 

 of the year (the rainy season) pours down from the 

 rivers at the northern end of the Lake. As in their 



