Devon County Geological Sites

Site reference no. SX79SW2 Name: Parford Wood

District: West Devon Parish: Drewsteignton

National grid ref: SX 713 902 OS sheets: 1:50k 191 1:25k 28 1:10k S79SW GS 1:50k 324 GridRef x y Lat Long SX713902 271300 90200 50.697164 -3.8236618

Locality description (address): Parford Wood, 2300m W20°S from Drewsteignton.

Nature of site: Old pit, now wooded

Geological / geomorphological features: Pit once worked in coarse sandstone and cemented gravels of probable Lower Tertiary age. Other similar deposits occur nearby at Bradford Pool [700910] and Great Tree Farm [705 906]. These deposits were worked for alluvial tin. in the early part of the 16th Century. Exposures are now rare although one [7136 9026] some way up the side of the pit showed over 1.5m of brown quartz/tourmaline grit. Most of the material seen is however debris such as the blocks of chalcedonically cemented quartz/tourmaline conglomerate and quartz grit seen near the entrance the pit at [7132 9010]. High up in the north-east corner at [7132 9038] over 3m of Head with a red brown sandy clay matrix contains many angular blocks of Crackington Formation sandstone along with large blocks of Quartz/tourmaline grit and conglomerate. Just below the Head there is a pronounced spring below which there are signs of yellow mottled grey silty clayey fine sand. Extremely sandy clay to silty clayey sand can also be seen in an excavation into one of the old waste dumps in the pit at [7122 9038]. The grit and conglomerate parts of the deposit bear a striking similarity to the Wooleigh Grit farther south east at Knowle Wood, Lustleigh. The deposits all lie in a NW-SE trending valley form which stretches from Sandy Park in the north-west towards Lustleigh in the south-east. Although no fault has been mapped down this valley, it seems likely that some structure, probably active in the Tertiary, was controlling both the deposition and preservation of these deposits which are almost certainly fluviatile in origin and deposited by a river flowing south-eastwards to the fluvio-lacustrine Bovey Basin.

Reasons for registration as a Regionally Important Geological / Geomorphological Site: An interesting example of Tertiary alluvial tin working and a comparison with the Wooleigh Grit locality at Lustleigh.

Site sensitivity: None Known

Safety: Safe

Interest groups: Schools. Years 17-18. University. Undergraduate - Research Professional geologists - Amateur geologists - General public.

Access and Parking: On the unclassified road to the south with a walk up the access track

Date of assessment (V = visited) : V 1998 E C Freshney

Site owner : National Trust- Estate Office, Castle Drogo

Other comments:

References: Blyth, F G H, 1962. The structure of the north-eastern tract of the Dartmoor Granite. Quart. Journ. Geol. Soc. , 118, pp435-53. Edmonds, E A, J E Wrght, K E Beer, J R Hawkes, M Williams, E C Freshney, and P J Fenning. 1968. The Geology of the country around Okehampton. Mem Geol. Surv Ormerod, G W. 1866. On the traces of tin streaming in the vicinity of Chagford. Trans. Devon Assoc., 1,pp124-8.