Patagonian Desert albeit to the west, where precipitation is higher, bushes are replaced by grasses. Topographically the deserts consist of alternating tablelands and massifs dissected by river valleys and canyons. The more western parts of the steppe host lakes of glacial origin and grades into barren mountains or cold temperate forests along valleys. Inhabited by hunter-gatherers since Pre-Hispanic times, the desert faced migration in the 19th century of Mapuches, Chileans, Argentines, Welsh, and other European peoples, transforming it from a conflictive borderland zone to an integral part of Argentina, with cattle, sheep and horse husbandry being the primary land uses. The Patagonian
Patagonian Desert contributing to the gravel sediments covering parts of the Patagonian. The desert is quite windy as well, a result of the rain shadow effect and descending cool mountain air. This wind helps make the Patagonian one of the largest sources of dust over the South Atlantic Ocean. On the west the Patagonian grasslands portion of the Patagonian Desert are bounded by nothofagus forests of the Magellanic subpolar forests. Volcanic rocks covers more than 120,000 km of the Patagonian Desert, mainly in the "Somun Cura Massif" (i.e. North Patagonian Massif) and the "Deseado Massif". Some other volcanic areas include the Pali-Aike