The Assynt area lies within the Moine Thrust Belt and is a classic locality in the history of the development of theories about thrust tectonics. 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. The peak itself consists of Cambrian quartzite, which also forms the ridge to Conival and the ground to the north and northeast of the peak. Torridonian sediments are only exposed around Conival.