190 THE PHYSICAL GEOGRAPHY OF THE SEA. 



with fresh vapor, winds that had ah^eady left rain enough behind 

 them to make an Amazon and an Oronoco of. 



391. Now that there has been such an elevation of land out of 

 the water, we infer from the fact that the Andes were once cov- 

 ered by the sea, for their tops are now crowned with the remains 

 of marine animals. When they and their continent weiif sub- 

 merged — admitting that Europe in general outline was then as it 

 now is — it can not be supposed, if the circulation of vapor were 

 then such as it is supposed now to be, that the climates of that 

 part of the Old World which is under the lee of those mountains 

 were then as scantily supplied with moisture as they now are. 

 When the sea covered South America, the winds had nearly all 

 the waters which now make the Amazon to bring away with 

 them, and to distribute among the countries situated along the 

 route (Plate VII.) ascribed to them. 



392. If ever the Caspian Sea exposed a larger surface for evap 

 oration than it now does — and no doubt it did ; if the precipitation 

 in that valley ever exceeded the evaporation from it, as it does in 

 all valleys drained into the open sea, then there must have been a 

 cliange of hygrometrical condition ther^. And admitting the va- 

 por-springs for that valley to be situated in the direction supposed, 

 the rising up of a continent from the bottom of the sea, or the up- 

 heaval of a range of mountains in certain parts of America, Africa, 

 or Spain, across the route of the winds which brought the rain for 

 the Caspian water-shed, might have been sufficient to rob them 

 of the moisture which they were wont to carry away and precip- 

 itate upon this great inland basin. See how the Andes have made 

 Atacama a desert, and of Western Peru a rainless country ; these 

 regions have been made rainless simply by the rising up of a 

 mountain range between them and the vapor-springs in the ocean 

 which feed with moisture the winds that blow over these now rain- 

 less regions. 



393. That part of Asia, then, which is under the lee of south- 

 ern trade-wind Africa, lies to the north of the tropic of Cancer, and 

 between two lines, the one passing through Cape Palmas and Me- 

 dina, the other through Aden and Delhi. Being extended to the 

 equator, they will include that part of it which is crossed by the 

 continental southeast trade-winds of Africa, after they have trav- 

 ersed the greatest extent of land surface (Plate YIL). 



