Trifter

WALLTOWN Crag in Central Northumberland carried Hadrian’s Wall for 2,000 years. Quarrying began here during the 187os and the crag was blasted apart to obtain the this immensely hard rock that was needed for road building. This work exposed the rock’s raw face and the Hard Rock Trial reveals the area’s geological history

This short walk starts at the Walltown Information Centre. The centre tells the story of the quarrymen who extracted Whin (an exceptionally hard dense grey rock. Whinstone is a Dolerite (a hard molten rock or magma that was injected under heavy pressure between the existing layers of sandstone deep below the earth’s surface.

Quarrymen were fortunate in this area as the Whin Sill is a widespread sheet of dolerite which underlies much of this region.

The walker follows the main track from the centre into the quarry, keeping the dry-stone wall with the pond to the right onto a small crag. People are advised to take care here as much of the rock is loose.

A stone carving on this face is an enlarged version of the fossils that are found in this area. These fossils lived in a shallow tropical sea that was here around 310 million years ago. Grey mudstone banks on both sides of the crag are formed from the sandstone that predated the Great Whin Sill.

The route follows onto to the main face of the quarry. The erratic granite and limestone boulders that abound in this part of the walk were transported from the Lake District and Scotland by immense glaciers during the various Ice Ages.                                           

Walkers continue along the footpath before climbing to the base of the cliff. They can now view the spectacular crags to the east that drew the attention of Hadrian to this area. One striking effect at this point are the large hexagonal columns that were formed as the dolerite cooled and began to split.

The footpath now climbs to the top of the slop at the south-east corner of the quarry. Visitors are now able to see the large number of small round holes that abound here in the rock.  These were formed when bubbles of gas or steam became trapped in the molten rock.

Secrets of the Stones is now almost over. A few more footsteps take the walker to a natural stone step that is formed from a finer grained type of dolerite. This smooth flat surface, which dips towards the trees is the top surface of the Great Whin Sill.

This is where the Hard Rock Trail ends and the walker has just travelled through the Great Whin Sill from its base to its upper surface.

A self guide leaflet to the Hard Rock Trail is available from the Walltown Information Centre.

Walltown is along an unnumbered road that runs from the B6318 or Military Road, just to the east of Greenhead.