The Cradle of Humankind: fossil country beside the Johannesburg road

Two very different reasons to leave the city share one stretch of road north-west of Johannesburg. The wildlife properties are the obvious one. The other is a block of cave-riddled dolomite that turned out to hold some of the most studied fossil deposits anywhere.

What the Cradle of Humankind is

It is a region, not a site. The name covers an area of farmland, grassland and low ridges north-west of Johannesburg, straddling the boundary country between Gauteng and the North West province, under which lies a network of limestone and dolomite caves.

Those caves have produced early hominin fossils in quantity, along with the remains of the animals that shared the landscape with them. That is the reason for the name and for the international attention. Above ground there is very little to look at that announces any of it, which is part of why visitors arriving with a mental picture of an excavation site are often briefly confused.

The name is recent and the boundary is administrative. It marks out an area for protection and for management, and it does not correspond to anything a visitor can see on the ground. Properties fall inside or outside it by survey line rather than by geology, which is why a farm on one side of a road can carry the designation and its neighbour cannot.

Why the caves are there at all

The geology does the explaining. The rock underneath this ground is dolomite, laid down in shallow water long before anything walked on land, and dolomite dissolves. Groundwater working along cracks over an extraordinarily long period hollowed out chambers and passages beneath the surface.

Where a chamber broke through to the surface it became a trap. Sediment washed in. Bone washed in with it, or fell in, or was carried in by predators and owls. The mixture cemented into a hard deposit that preserved what it contained, and that deposit is what researchers have been taking apart ever since.

The important consequence for a visitor is that the fossils were not lying in the open. They were locked in rock inside caves, and getting them out has been slow, technical work. Lime quarrying in the region, which is what first opened several of the caves, is the reason anybody knew they were there.

The World Heritage listing

UNESCO inscribed the area on the World Heritage List in 1999. The listing is not a single cave but a cluster of fossil-bearing sites, of which Sterkfontein is the best known outside academic circles.

What the listing protects is the ground rather than any particular find. Sites in this region are still being worked, and the science moves: dating methods have been revised more than once, and figures published a decade ago are not always the figures in use now. Any confident-sounding number attached to a specific fossil is worth checking against whoever published it most recently.

The landscape above ground

Drive through it and it reads as ordinary highveld farm country. Pale grass, thorn trees along the drainage lines, low quartzite and dolomite ridges, cattle, game fencing, the occasional dam.

A good deal of the area has been converted from farming to conservation and to visitor use, which means fences and antelope where there used to be maize. Some of the properties in the area keep game; some keep predators. That mixture, ordinary farmland turning gradually into managed wildlife land, is the same process that produced the reserve country described on the Johannesburg safari page.

Water is the other visible feature. The dolomite that holds the caves also holds groundwater, and several of the region's springs and small streams rise from it, which is why the valleys hold trees when the ridges above them hold only grass. That pattern, green lines running through pale country, is the easiest way to read the underlying rock from a moving car.

Why the old park sat on the same route

The Lion Park stood in Gauteng, north-west of Johannesburg, at Honeydew near Lanseria, on a road that a great many people were already driving toward the Cradle of Humankind.

That is not a coincidence so much as a consequence. A wildlife attraction wants to be on a road that already carries visitors, and after the World Heritage listing this particular road carried a great many. Two stops with nothing in common, a cave system and a predator camp, became a single day out because they were near each other and because neither took long. The way those days were assembled follows directly from it.

The park is no longer at that site. Its profile covers what it was, and the operation now trades under another name near Hartbeespoort.

Two subjects that keep getting confused

Because they share a road, the fossil landscape and the wildlife properties get bundled together in a way that occasionally misleads. They have no institutional relationship. The heritage listing does not cover the game properties, and a wildlife park in the area is not a heritage site because it happens to sit within the region's boundary on a map.

The confusion runs the other way too. Visitors sometimes expect a fossil site to have animals, or expect the caves to be part of a reserve. They are separate operations with separate purposes that happen to be neighbours.

A landscape still being read

Excavation in the region has been going on for the better part of a century and has not stopped. New material comes out of the caves, older material gets re-examined with methods that did not exist when it was found, and interpretations shift accordingly.

For a reader that means something slightly awkward: the popular account of what these caves contain is always a little behind the published one, and the published one is contested in places. The safest thing anyone can say about the Cradle of Humankind is that it is a dolomite landscape which preserved a great deal, that it has been under study for a very long time, and that the study is not finished.