One of the most significant excavation sites is at the foot of Mount Olorgesailie in Kenya which is the first site where evidence of ancient human artifacts is found from that specific time gap. Homo erectus was an early human species that hunted in groups, and the evidence found there is one of the earliest examples of organized game hunting and processing. There have been extremely old early human fossils found from 3 million to 1.5 million years but there is a big gap between 1.5 million years and about 500,000 years in the fossil record. Geological formations are used to determine the dating of such fossils. But in Ethiopia, there were the earliest examples of tools used by early men like sharpened pebbles for cutting meat, or hand axes.