4 R. A. F. PENROSE, JR. 



10,000 to over 20,000 feet, while the Coast Range is lower, from 3,000 

 to 7,000 feet, though sometimes more. The Coast Range is often 

 characterized by rounded summits and smooth slopes, in marked con- 

 trast with the bold angular contour of the Andes. In some places 

 the Coast Range is" prominently marked, while in others it is little 

 more than the escarpment of an interior plateau as it breaks off to 

 the sea. 



Both the Andes and Coast Range follow a general north-and- 

 south course, and between them is an intervening belt of lower 

 country known as the central or longitudinal valley. This so-called 

 valley, however, is not a single continuous drainage area bordered 

 by two mountain ranges as might be supposed, but is a series of 

 elevated basins, forming rolling plains or plateaus, more or less 

 separated by transverse ranges, and draining independently of each 

 other into the Pacific Ocean. In some places the mountains on the 

 east and west approach so closely to each other that their foothills 

 blend together, almost obliterating the intervening basin region; 

 in other places they separate, and the basin region broadens out to 

 many miles in width (see map, Fig. i). 



In northern Chile this basin region is especially well marked in 

 the provinces of Tarapaca, Antofagasta, and northern Atacama. 

 It is here an elevated arid country and includes the Tamarugal 

 Desert on the north and the Desert of Atacama on the south.' It is 

 of a generally fiat or undulating character, from less than 2,500 

 feet to over twice that height above the sea, and studded with small, 

 rounded hills, some of which rise considerably higher than the sur- 

 rounding plateau (see Fig. 2). Its surface is dry and sandy, very 

 few streams intersect its parched expanse, and vegetation is almost 

 totally absent.^ This region is known as the pampa, a term applied 

 somewhat indiscriminately not only to the whole arid region, but 



1 The Tamarugal Desert includes most of the interior basin region of the province 

 of Tarapaca and the northern part of the province of Antofagasta. The Desert of 

 Atacama includes the southern part of Antofagasta and the northern part of the 

 province of Atacama. 



2 Farther south, in central Chile, the basin or valley region becomes a rich fertile 

 country under the influence of the plentiful rainfall there; and still farther south, in 

 southern Chile, vi^here the basin region is more or less submerged in the ocean, the rain- 

 fall increases so much as to make one of the wettest parts of the world; but in this 

 northern section the dry desert character of the country is its distinguishing feature. 



