FIGURE 1. A simplified map of Mpumalanga Province, South Africa.
From the following article:
Geochemical evidence for terrestrial ecosystems 2.6 billion years ago
Yumiko Watanabe, Jacques E. J. Martini and Hiroshi Ohmoto
Nature 408, 574-578(30 November 2000)
doi:10.1038/35046052
The figure shows the main geological units, and the localities of organic-rich palaeosols (Schagen, Elandshoek, Kalkkloof) (modified after ref. 9).