Complex sentence: The use of the cowry currency gradually spread inland in Africa, and about 1850 Heinrich Barth found it fairly recognized in Kano, Kuka, Gando, and even Timbuktu.
Split into simpler sentences: The use of the cowry currency gradually spread inland in Africa. By about 1850 Heinrich Barth found it fairly widespread in Kano, Kuka, Gando, and even Timbuktu.