In this paper we present the results of surveys carried out in February 2016 along a palaeo-drainage system near the village of Bisyah. We report first on the geological prospection, which was our main goal, and then present our discovery of the only known localities in north Oman of large Kombewa flake production (>10 cm up to 20 cm). Among the scatter of artefacts, we found cores and large Kombewa flakes with two opposed bulbs of percussion, a technology that had not been known in this region until now. In spite of the local features, the typo-technological traits of the artefacts suggest that at least part of them resemble in some way the Acheulean techno-complex, but there are still many questions remaining on the age of these artefacts.