Area: 9.7 hectares.

Description and Reasons for Notification: 

This site contains a typical example of one of the largest massive alkali dolerite greenstone bodies in this area. The sill-like body intrudes and incorporates within it black argillite rafts of Lower Carboniferous (Visean) age. It not only shows a variety of primary internal textures and mineralogies, but also exhibits excellent curved columnar jointing only occasionally seen in the massive greenstones. This body (and many others in the area) lie within the aureole of the Dartmoor granite and show the superimposed mineralogical effects of low-grade contact metamorphism.