20 NATURAL REGIONS OF ARGENTINA 



lengthen. In one part of Patagonia they still form 

 a continuous cap, an " inland sea," concealing the 

 rock over the entire central zone of the Cordillera ; 

 though they are only the shrunken remainder of a 

 glacial cap which was once far more extensive. Here 

 ice was the chief sculptor of the scenery. It has made 

 elevated tablelands, broadened the deep valleys which 

 cut the flank of the mountain, polished their sides, and 

 deposited at the point where they open out the amphi- 

 theatres of the moraines, behind which the waters have 

 accumulated and formed lakes ; and these lakes stretch 

 back like fiords to the heart of the Cordillera, and are 

 the pride of Patagonia. 



The waters of these moisture-laden mountains have, 

 to the east, carved out the Patagonian tableland. 

 It is crossed by broad and boldly cut valleys, several 

 of which, abandoned by the rivers which scoured 

 them, are now dead valleys. The rubbish from the 

 wearing down of the mountains and the glacial moraine 

 has been spread over the whole face of the tableland 

 in the form of beds of gravel. But the rivers that 

 rise in the Andes cross a country of increasing aridity 

 as they descend eastward. There is no tributary to 

 add to their volume. There is none of that softening 

 of lines, of that idle flow of a meandering stream which 

 characterizes the final stage of a river in a moist 

 district. Their inclination remains steep, and their 

 waters continue to plough up coarse sediment ; and 

 everywhere, up to the fringes of the valleys, the fluting 

 of the sandstone and steepness of the cliffs bear 

 witness, like the edges of the hamadas of the Sahara, 

 to some other form of erosion than that effected by 

 running water — the influence on the country of the 

 westerly winds. On the tableland the wind polishes 

 the rounded pebbles, makes facets on them, and gives 

 them the colouring of the desert. 



Thus from the north to the south of Argentina 

 there is a complete contrast in the way in which the 



