The Laetoli hominid footprints dating back some 3.6 million years discov-ered by Leakey in 1978 is an archaeological site of great importance in understanding the human evolution. The footprints of hominids, animals, and birds cast in the volcanic ash consolidated into tuff deposits are also an insight into the evolution of the whole biogeosystem of this area dominated by volcanic activity. The volcanic ash deposits consolidated into tuffs are a marker which sets the base line for tracking the further sediment transport in the catchment of this historic site. The surface of the tuff exposure along the Garusi river carrying the footprints shows no signs of weathering and the soils of the area form in subsequent sediments that filled the valley after the deposition of the tuff material. Following the deposition and consolidation of the airfall tuffs, the biogeosystem of the Laetoli gorge and its surroundings experienced a complex evolution which led to formation of the present-day soil cover. The study of clay mineralogy of these soils has provided interesting insights into the evolution of this system.