Natural England - High Force, Teesdale (part of the Upper Teesdale SSSI)

High Force, Teesdale (part of the Upper Teesdale SSSI)

Location and Access Information
Grid Reference: NY 890280

High Force

High Force Waterfall cutting through
hard Whin Sill dolerite.

The site is located alongside the B6277, 7km north-west of Middleton in Teesdale. Car parking is available with picnic site and gift shop. There is then a woodland walk to High Force. For more information see link

Geological Interest

At a number of locations around County Durham intrusions of igneous rock are associated with the Carboniferous rocks of the area. These intrusions take the form of sills, tabular sheet-like bodies of igneous rock. The Whin Sill is an excellent example of a sill composed of a type of igneous rock known as a dolerite. This, originally molten rock, was intruded into the surrounding Carboniferous Limestone approximately 300 million years ago at the end of a period of large-scale mountain-building. Because of the hardness of the dolerite when compared with the surrounding sedimentary rocks, the Whin Sill forms a series of imposing features in the landscape. These include High Force, where the River Tees flows over the lip of the sill to form, at 30m high, England’s largest waterfall.