THE GREAT SHEEP-FARMS 151 



quen. This occupies the bottom of a closed depression, 

 at an altitude of 3,000 feet, dominated on every side by 

 a plateau of lava, toward which, in the south, a number 

 of important valleys run (Nahuel Niyeu, Quetriquile, 

 Maquinchao). These valleys rise in the south in the 

 basalt plateau, at a height of 4,000 and 4,700 feet, 

 and have no running water except at their upper ends. 

 South of Carilaufquen they open upon a broad plain, 

 round which there is a sombre cornice of lava, about 

 350 feet high. Water has collected on the plain, which 

 consists of alluvial beds redistributed by wind : angular 

 pebbles from the terraces, fine dust from the mallinas, 

 and sand from the dunes round the lake. 



This region is much better than that of the Cerros 

 Colorados. There are many springs at the base of 

 the lava-flows, on the sides of the valleys, and it has as 

 yet not been necessary to look for the subterranean 

 sheets which accompany some of the valleys. The 

 elevated basin of the Quetriquile, though it is only 

 occupied by intrusos, seems to have a particularly high 

 pastoral density, and, I am told, feeds 500,000 sheep. 

 In the western part of the region the spring is late, and 

 there is risk of snow during the lambing season. There 

 are, however, no rams there ; the lambs are brought 

 from Maquinchao. This arrangement of special zones 

 for the multiplication of the flock enables them rapidly 

 to improve the breed. Here again there are no removals 

 of the animals to a great distance in order to use 

 the pasture. The vegetation of the valleys suffered 

 from the continuous presence of the flocks during the 

 years of drought before 1914 ; the reproduction of 

 useful grasses was prevented. There is, however, 

 less danger here than on the Cerros Colorados, because 

 the mallinas are extensive, and they suffice for feeding 

 the sheep during the periods when the manantiales of the 

 tableland dry up, and the animals are confined to the 

 valleys. 



The fifth region comprises the high ridge which divides 



