The rocks under Lambston are made from sediments. Laid down in the deep ocean 430-450 million years ago and then compressed and folded. What would have been flat layers, now stand almost on edge. The rock layers form belts running south-east to north-west across the parish. Most of the parish is on shales and mudstones but at Portfield Gate and in a narrow band across Sutton Mountain are harder sandstones. The sandstone is probably what gives Sutton Mountain its steep south slope.
This PDF (click on link below) is a copy of the poster which we used for the 2017 Parish History Exhibition in Sutton. If you click on the link it should open on your screen. (If you have any problems seeing this, please let me know; jok_mathieson@hotmail.com).