 The mountains of Ben More Assynt and Conival sit on the Ben More thrust sheet which is bounded by the Ben More Thrust below and the Moine Thrust above.The thrust sheet consists of Lewisian gneiss with a cover of Torridonian sandstones and Cambrian quartzite.Lewisian gneisses are exposed to the south and southeast of the peak of Ben More Assynt and forms the ridge to the South Top, making it the highest located example of this rock type.