History of Somalia The oldest evidence of burial customs in the Horn of Africa comes from cemeteries in Somalia dating back to the 4th millennium BC. The stone implements from the Jalelo site in the north were also characterized in 1909 as important artefacts demonstrating the archaeological universality during the Paleolithic between the East and the West. According to linguists, the first Afro-Asiatic-speaking populations arrived in the region during the ensuing Neolithic period from the family's proposed urheimat ("original homeland") in the Nile Valley, or the Near East. Other scholars propose that the Afro-Asiatic family developed in situ in the Horn, with its
Geology of Somalia and island arcs. In the Early Jurassic, the supercontinent Gondwana, which included Africa, began to break apart. The marine transgression of the Tethys Ocean flooded large parts of East Africa and Arabia and new sedimentary rock units were deposited. In the west of Somalia, the Cretaceous at the end of the Mesozoic brought crustal upwarping, which is preserved in the Yesomma Sandstone. Two major sedimentary basins began to form in Somalia during the Mesozoic, the Somali Coastal Basin and the Luuq-Mandera Basin, both filled with up to five kilometers of sedimentary rock. The basins formed due to the movements of