Stones that nobody can explain are scattered across the Gambian countryside, and Kerbatch has some of them. The stone circles of Senegambia, a World Heritage site since 2006, are a group of more than a thousand megaliths in about thirty circles, set in a band of land along the river Gambia and into Senegal. Each stone is a carved pillar of laterite, a rust-red, iron-rich rock that is cut from the ground when it is soft and hardens in the sun, and they stand in rings of ten to twenty, sometimes with a larger stone set to one side. They were raised between roughly the third century BC and the sixteenth century AD, and they mark burials, some of which have been excavated and found to hold skeletons and grave goods.
Nobody knows who built them. The local people say the circles were always there, and archaeologists link them to ancient communities of farmers and ironworkers who lived along the river, but the beliefs behind them are lost. Kerbatch is a smaller group than the better-known sites at Wassu, which has a small museum and eleven circles, and at Sine Ngayene in Senegal, which has the largest number of stones, but there is something affecting about standing in a quiet field among a ring of old pillars with a view of acacia and baobab trees.
The roads here are a typical West African mix. The main highway along the south bank of the Gambia is a long, straight road with a patched surface, and the pace is determined by potholes, goats, donkey carts, minibuses and the occasional police checkpoint, which is normally polite and brief. The dry season, from November to May, is the only sensible time to ride, since the rains from June to October flood the tracks and turn the red laterite into mud. In the middle of the day the heat is intense, so start early, carry plenty of water and wear a light, breathable layer.
Karantaba, with about seventeen hundred people, and Kass Wollof are small villages, so fill up with fuel in a larger town such as Soma or Farafenni before you leave. The village women sell groundnuts, mangoes and sweet tea, and the hospitality is warm, with greetings that can go on for some time.