Kapthurin Formation

The Kapthurin Formation is a basalt outcrop in Kenya near Lake Bogoria and Lake Baringo.
Part of the East African Rift System, it is also an important archaeological site in the study of early humans who occupied the area and left Acheulean stone tools and animal bones behind.
Argon–argon dating of volcanic ash overlying ochre fragments found there has dated what may represent some of the earliest human aesthetic sensibility to 285,000 years ago. The ochre fragments must have been brought to the site by human agency and may have been used as body adornment.
Sources.
Tryon, CA and McBrearty, S, 2002, "Tephrostatigraphy and the Acheulean to Middle Stone Age transition in the Kapthurin Formation, Kenya", "Journal of Human Evolution" 42, 211–35, qtd in Scarre, C (ed.) (2005). The Human Past, London: Thames and Hudson. .