Glenthorne () is a 13.3

hectare The hectare (; SI symbol: ha) is a non-SI metric unit of area equal to a square with 100- metre sides (1 hm2), or 10,000 m2, and is primarily used in the measurement of land. There are 100 hectares in one square kilometre. An acre is ...

geological Site of Special Scientific Interest A Site of Special Scientific Interest (SSSI) in Great Britain or an Area of Special Scientific Interest (ASSI) in the Isle of Man and Northern Ireland is a conservation designation denoting a protected area in the United Kingdom and Isle o ...

in the parish of Oare within the

Exmoor Exmoor is loosely defined as an area of hilly open moorland in west Somerset and north Devon in South West England. It is named after the River Exe, the source of which is situated in the centre of the area, two miles north-west of Simonsbath ...

National Park, on the border of

Somerset ( en, All The People of Somerset) , locator_map = , coordinates = , region = South West England , established_date = Ancient , established_by = , preceded_by = , origin = , lord_lieutenant_office =Lord Lieutenant of Somerset , lord_ ...

and

Devon Devon ( , historically known as Devonshire , ) is a ceremonial and non-metropolitan county in South West England. The most populous settlement in Devon is the city of Plymouth, followed by Devon's county town, the city of Exeter. Devo ...

, notified in 1989. Glenthorne is a

Geological Conservation Review The Geological Conservation Review (GCR) is produced by the UK's Joint Nature Conservation Committee and is designed to identify those sites of national and international importance needed to show all the key scientific elements of the geological ...

site because of the Trentishoe Formation of the Hangman Sandstone Group. The Hangman Sandstone represents the

Middle Devonian The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, w ...

sequence of North Devon and Somerset. These are unusual freshwater deposits in the Hangman Grits, which were mainly formed in desert conditions.

References

External links

English Nature website
(SSSI information) {{SSSIs Somerset geological Sites of Special Scientific Interest in Devon Sites of Special Scientific Interest in Somerset Sites of Special Scientific Interest notified in 1989 Geology of Devon Geology of Somerset