Societies? ?and ? ?Empires? ?of? ?Africa Chapter? ?15 Trade? ?Grows? ?across? ?the? ?Sahara - During? ?the? ?Neolithic? ?period,? ?the? ?Sahara? ?starts? ?to? ?dry? ?out? ?so? ?people ? ?have? ?to? ?move ? ?out of? ?the? ?Sahara ? ?Desert.? ?Some? ?people? ?move? ?into? ?the? ?savanna? ?region,? ?a ? ?grassland ? ?area that? ?offered? ?land? ?for? ?farming? ?and? ?pasturing ? ?herds. - Trade? ?network? ?emerges? ?across? ?savana - Trade? ?dominated? ?by? ?gold? ?and? ?salt - Gold? ?widely? ?available,? ?transported ? ?to? ?N ? ?Africa? ?to? ?Europe - In? ?exchange? ?for? ?gold,? ?w? ?Africans? ?get? ?salt? ?(very? ?important) - Salt? ?available ? ?in? ?sahara? ?but? ?not ? ?in? ?savanna