The "Alkummer" is an imposing dolomitic gorge. The dolomite forms steep rock faces and is divided by a network of vertical cracks and fractures (crevices). Water trickles through the crevices in the dolomite and accumulates on the underlying marls, a clay-rich rock. For a long time, the rock faces of dolomite slip down on the softened marls and break up into large stones. The narrow, accessible rock passage "Alkummer" was created because the blocks did not completely tipped over here.
The Alkummer is located directly on Route 1 of the Mullerthal Trail. Also on the local circular route R8, the Alkummer can be hiked, which runs in places on the Mullerthal Trail. Parking is available in Steinheim and below at the N10 at the Sûre.