Devon County Geological Sites or Regionally Important Geological / Geomorphological Sites - RIGS

Site reference no. SX65NW1 Name: Ivybridge and the Erme Valley

District: South Hams Parish: Ivybridge and Ermington

National grid ref: 6330 5576 - 6366 5750 OS sheets: 1:50k 202 1:25k 1357 1:10k SX65 NW GS 1:50k 349

GridRef x y Lat Long SX636562 263600 56200 50.38982 -3.9201687

Locality description(address): Ivybridge town area and the valley of the River Erme to the north and south.

Nature of site : River valley and gorge crossing the margin of the Dartmoor Granite and related features.

Geological / geomorphological features: Dartmoor Granite, lithological variations at margin. Contact between granite and metamorphosed sediments (Carboniferous). Further exposures showing decreasing grade of thermal metamorphism in Carboniferous and Devonian slates. Boulder and cobble alluvium above knick-point at head of the Erme Gorge of probable Pleistocene (Ice age) date. Its presence and extent is indicated by the use of the boulders in old field banks and as building material in the lower parts of Ivybridge.

Reasons for registration as a Regionally Important Geological / Geomorphological Site : A readily accessible set of geomorphological and geological features of considerable value for teaching purposes. Contacts between the Dartmoor Granite and the metamorphosed sediments on its margins are rarely so well exposed and the boulder outwash fan is a large geomorphological and geological feature unmatched in southern England.

Site sensitivity: No particular sensitivity. Care is required when collecting rock specimens beside the river to avoid unsightly scarring of water worn surfaces.

Safety: Essentially safe. Care is required near the river, particularly in conditions of high flow.

Interest groups: Schools. Primary - Secondary - 6th Form . University. Undergraduate - Research Professional geologists - Amateur geologists - General public. (Underline)

Access and Parking: Easy access by public roads and footpaths. Public car parks available in Ivybridge. Some on road parking available opposite Stowford Mill and below the railway viaduct.

Date of assessment (V = visited) : V 28th November 1994 . R T Taylor

Site owner : Multiple ownership. Parts managed by South Hams District Council and the Dartmoor National Park Authority

Other comments: Only part of the Erme Valley around Ivybridge has been examined in the present RIGS assessment. It is likely that other features of geological and geomorphological interest occur further up and down stream in the area covered by the Erme Valley Trail. Some parts of the area examined are accessible to the disabled with assistance.

References: Gilbertson, D D and Sims, P C, 1974, Some Pleistocene Deposits and Landforms at Ivybridge, Devon. Proceedings of the Geologists Association, Vol. 85, pp. 65-77. Gilbertson, D D, 1973. The Construction of Hedgebanks at Filham Moor, Ivybridge. Quarterly Journal of the Devon Trust for Nature Conservation. Vol. 5, pp. 41-4 . Guide to the Erme Valley, South Hams Environment Service, South Hams District Council.