Senegambian stone circles

Why this is extraordinary

Between the Gambia and Senegal rivers, more than 1,000 stone circles stand in a band about 100 kilometres wide and 350 kilometres long. Four groups are inscribed together: Sine Ngayène and Wanar in Senegal, Wassu and Kerbatch in The Gambia. Those four hold 93 circles. Sine Ngayène is the largest, 52 circles including one double circle, and 1,102 carved stones. A quarry about a kilometre east still shows where stones were cut, and the sources of about 150 of them can be traced. The pillars are laterite, shaped with iron tools into near-matching cylinders or polygons, on average about two metres high, some up to about seven tonnes. A circle holds between 8 and 14 pillars and is about 4 to 6 metres across. Frontal stones stand outside many circles. Wanar has nine lyre-shaped, or bifid, stones. Kerbatch has a bifid stone of its own.

The listing dates the material from excavated mounds to between the 3rd century BCE and the 16th century CE, more than 1,500 years of one kind of monument. At Sine Ngayène, single burials seem to come before the multiple burials that belong with the circles. At Wassu, a charcoal sample of 1,200 plus or minus 110 radiocarbon years before present was read as 927 to 1305 CE, from a burial dug in the 1960s. A date on a body is a date on that body. It is the circle’s date only if the burial and the pillars are one event. Laterite has no carbon of its own. Few circles have been dug. The builders are not named to a kingdom or a modern people in the listing. The inscription calls them a prosperous, organised society that kept the practice up. That is a description of the work, not a genealogy.

Purpose is burials first. Bodies, pottery, iron, and ornaments have come out of the mounds that sit with the circles. A circle can also be read as a meeting mark or a territory stone, because most of the monuments are unexcavated and a burial can be later than the ring. The nomination is plain that this complex is funerary, and it contrasts the circles with European rings that are sited on a skyline for a solstice. No peer-reviewed azimuth table for Wassu or Sine Ngayène is in the sources used here. A filmed demonstration has pointed from one stone toward a solstice sunset and an equinox. A film is a reading. It is not a published survey. What can be taught without fake numbers is the geometry. At this latitude the equinox sun rises due east, and a frontal stone set east of a circle is exactly where that test would be made. The June sunrise is well north of east, the December sunrise well south of east. Until the frontal stones are measured, they are a candidate, not a calendar.

The pin is Sine Ngayène. Wassu and Kerbatch, on the Gambian side of the same river system, are the same tradition and are noted with this room rather than given a second country page.