602 



THE NATURE BOOK 



Photo^^raph by G. Binx:!<ey, Headin^ity. 



"THEY NESTLE UNDER THE STEEP CLIFFS OF MOUNTAIN CIRQUES." 



Llyn Llyn-Caws. 



dered near the hills 

 with torrential gravels 

 and sand. But the 

 water flowing from the 

 high grounds contains 

 salts in solution, and 

 as these are left be- 

 hind when the water 

 is evaporated, deposits 

 of salt, gypsum, borax, 

 and other substances 

 are left behind. Soil 

 impregnated with 

 these substances is un- 

 fit for the support of 

 hfe, and the places 

 covered by this be- 

 come deserts. Salt 

 lakes are found in all 

 desert areas. Although 

 the climate of our 



of Africa. It is of gigantic size, and is country does not admit of the production 



marked by a chain of lakes — the Dead Sea, of salt lakes at the present day, we have 



Lake Rudolf, and others — some of which reason to believe that the salt deposits of 



have floors beneath the level of the sea. Cheshire and other places represent accu- 

 Another great valley of depression mulations formed in lakes when the rate 



exists in the Western States of North of evaporation exceeded the water brought 



America. In Oregon, Nevada, and in Cah- into them by streams. J. Lomas. 



fornia, are vast 



areas 300 feet 



or more below 



sea level. They 



represent 



blocks which 



have fallen be- 

 tween moun- 

 tains rising to 



8,000 to 9,000 



feet above the 



sea. Torrents 



flowing from 



the high 



grounds in the 



rainy season 



produce lakes 



in the depres- 

 sions, and in 



arid regions 



the waters are 



evaporated 



during the dry 



season. Thus 



there remain 



only flat 



11 1 /■/Vi.-'i';,' ;■.///; hy I o)ftk-tn:,on, Liverpool, 



muaay cie- "the ground is stkewn with glacial debris." 



posits, bor- Easdale Tarn. 



