190 
THE PHYSICAL GEOGRAPHY OF THE SEA. 
with fresh vapor, winds that had already 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 were 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 supphed 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 
change of hygrometrical condition there. 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 w^ater-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 VII.). 
