Area: 6.7 hectares.
Description and Reasons for Notification:
In Dartmoor National Park. Listed as of national importance in the Geological Conservation Review.
The knoll of Brent Tor is one of the few well-exposed examples of Lower Carboniferous basaltic hyaloclastites in Devon. From the limited outcrop pattern submarine volcanism probably built a small localised high-level hyaloclastite mound on the seafloor. The stratigraphically upper portion of the sequence is poorly bedded and demonstrates the effect of water current reworking, carrying volcanic debris down slope for a considerable distance. As Hercynian submarine volcanism is generally represented by the development of pillow lavas, this locality is a rare example of a Carboniferous eruption event that produced basaltic volcaniclastites.