Thrislington Plantation NNR is the most valuable wildlife site on County Durham’s magnesian limestone. Main habitats: lowland grassland. Features of interest This rock originally formed in a shallow tropical sea some 250 million years ago, and now outcrops in only a few places in northern England. It has weathered to form thin lime-rich soils on which unique grasslands have developed. Over the years the effects of agricultural change, mining and quarrying have reduced the limestone grassland to a tiny remnant of its original area. The limestone grassland at the site supports scarce plant species, including blue moor grass, small scabious, rock-rose, and dark red helleborine. Insects abound with many unusual species present. Two notable examples are northern brown argus butterfly and glow-worm. The reserve is adjacent to a working quarry which makes some access restrictions necessary. Organised groups must pre-book. For more details (and a copy of a species guide for the site), email the reserve manager Joe Davies joe.davies@naturalengland.org.uk. The best time to visit is between May and late August. Directions The reserve is 1 kilometre west of the A1(M), 10 kilometres south of Durham, 12 kilometres north east of Bishop Auckland, and 1 kilometre east of Ferryhill village, on the A167. By car, access to the site is via minor roads from the A167 and the village of Cornforth, 1.5 kilometre to the north. The site is immediately south of a working quarry operated by Lafarge Aggregates. There is a car park adjacent to the quarry offices but this is only available to pre-booked groups. There is a laybay near the reserve’s entrance on the minor road to Cornforth. The nearest train stations are Durham and Bishop Auckland. For bus services see Traveline. Contact For more information contact the NNR site office on tel: 0191 586 0004