The Ludlow Anticline
The Ludlow Anticline is a geological structure in North-West Herefordshire which runs from Ludlow in the north-east to Presteigne in the south-west. This feature is created due to the warping of the Silurian limestone and siltstone rocks over ancient rocks that lie beneath, creating an undulating landscape in the shape of an upfold: an anticline. The area is also famous for a number of fortifications, including the Bronze Age fort at Croft Ambrey, the Roman fort at Leintwardine, and the Norman Wigmore Castle, all of which have used the local Silurian stone. The village of Wigmore lies below the castle and has used this stone in several buildings and long lengths of wall down the two main streets, as well as for the ancient church, giving the village a strong stone character.
If you look carefully at the stone across this area you will notice that it becomes stronger and darker towards the west, as at Wigmore. This is because during Silurian times these rocks were being deposited as sediments on an ancient sea bed and that sea was getting deeper towards the west. As a result, the detailed nature of the sediment changes, from sediment richer in fossils and calcite mud in the shallower water to the east to sediment which is denser in the deeper water to the west, with associated changes in strength and colour.