GUAJIRA PENINSULA — CRIST 341 



niscent of the sand wastes of the Sahara are encountered. In the 

 shelter of the first line of dunes, in certain sectors, coconut groves 

 have been planted, which anchor a considerable population. Slightly 

 farther inland fields of millets can survive on the thin deposits of 

 sand. Between Paraguaipoa and Sinamaica the sandbar borders long 

 stretches of salt flats, which are exploited by the federal government. 



The rugged part of the peninsula lies northeast of the well-defined 

 fault lines, where mountains up to 900 meters in elevation are found. 

 The cores of the Serranias de Cocina, de Jarara, and de Macuira are 

 formed largely of igneous intrusives, and deposits of recent alluvium 

 in the form of coarse rubble are found at the base of these low moun- 

 tains. Extensive alluvial fans and terraces on the windward sides 

 of these igneous formations seem to be at two levels, the first and 

 higher level probably having been deposited when the mountains were 

 higher and were therefore able to wring more moisture out of the 

 winds. At the base of the leeward slopes, over the area surrounding 

 the shallow, bottle-necked embayment known as El Portete, thick de- 

 posits of unconsolidated sands and silts have been laid down. 



Just to the south of the Serrania de Cocina, striking almost east- 

 west, is an especially good section of the Cretaceous, with the caves 

 and sinkholes typical of Karst topography. The whole complex of 

 igneous cores and of indurated sedimentary deposits is in places cut 

 by dikes of igneous intrusives. 



Roads and trails in this rugged, mountainous part of the Guajira 

 traverse bare windswept terraces of recent alluvium, mesalike plat- 

 forms of sedimentary deposits and of igneous extrusives, and canyons 

 deeply incised into formations of limestones and shales, slightly dip- 

 ping to vertical. 



The Guajira Peninsula is a dry land, where evaporation far ex- 

 ceeds precipitation, as in so many parts of the globe at 10° to 15° 

 north or south of the Equator. For where winds blow most of the 

 time equatorward they are increasing in temperature, and as their 

 temperature increases their capacity to absorb moisture increases. 

 Hence they are drying winds and, when persistent, they create a 

 situation in which evaporation is steadily greater than precipitation, 

 with the result that desert or semidesert conditions prevail. This 

 is true wherever such winds, the trade winds, blow for most of the 

 year over a stretch of land of low elevation, whether it be in Africa 

 or in America, whether at 10°-15° north or south of the Equator. 

 It is true of the small, low-lying islands of the Caribbean, such as 

 Curagao and Margarita, as it is of most of Falcon, on the mainland 

 of northern Venezuela, and as it is of the Guajira Peninsula. And 

 the winds in the Guajira are vigorous enough to dry out and pick 

 up sand from the beach for many miles and blow the particles in- 



