Excavations at Kathu in the Northern Cape province of South Africa have produced tens of thousands of Earlier Stone Age artefacts, including hand axes and other tools estimated to be between 700,000 and one million years old - a massive deposit of Acheulean artefacts. The site is around 56 km west of Wonderwerk Cave, where a sequence of Earlier Stone Age occupation has produced early evidence of fire.
     Kathu Townlands shows high-intensity stone tool production, interspersed with exposures of bedrock, calcium carbonate concretions, and sand. Calcium carbonate concretions - calcretes - are a common feature in the area, and figure significantly in the deposits in the vicinity of the site. The bedrock outcroppings are dominated by chert - ideal for stone tool manufacture - and the availability of high quality raw material is likely a major reason for repeated exploitation of the resource, and the high density of stone tool and knapping debris.
     The site is one of a grouping of prehistoric sites known as the Kathu Complex. Other sites include Kathu Pan 1, which has produced fossils of animals such as elephants and hippos, and - from a level dated to half a million years ago - the earliest known evidence of tools used as spears.
     The Townlands site was brought to the attention of archaeologists in 1980 by the manager of the property, who had observed workmen using gravel composed primarily of artefacts to repair roads. Excavations were first conducted in 1982. In August 2013 excavations were undertaken to mitigate the destruction caused by building work on a portion of the known deposit.
     These dense and broadly distributed archaeological deposits pose methodological and management challenges. The town is rapidly expanding, and development is directly threatening deposits beyond the declared National Heritage site area.
     Together with the other parts of the complex, this site presents a challenge to reconstructions of hominin adaptations during the Early-Middle Pleistocene. Michael Chazan, Director of the Archaeology Center at the university, emphasises the scientific challenge posed by the density of the traces of early human activity in this area: "We need to imagine a landscape around Kathu that supported large populations of human ancestors, as well as large animals like hippos. All indications suggest that Kathu was much wetter, maybe more like the Okavango than the Kalahari. There is no question that the Kathu Complex presents unique opportunities to investigate the evolution of human ancestors in Southern Africa."
     The occurrence of a low density Acheulean occupation at Wonderwerk Cave suggests significant differences in the intensity of hominin activity between the two flanks of the Kuruman Hills. The density of archaeological remains within the Kathu Complex is likely related to local availability of water. It is intriguing to consider the possibility that the hominin occupation of Wonderwerk Cave during the Acheulean may be the result of seasonal mobility of small groups of hominins dispersing from the core occupation area on the western flanks of the Kuruman Hills.

Edited from PlosOne, Science Daily (24 July 2014), Popular Archaeology (25 July 2014)