A narrow strip of grassland straddling the Mill Burn as it falls though the edge of the conifer plantations of Harwood Forest. Butterwort is common on the wet edges of the burn, and uncommon species such as green spleenwort fern, grass-of-Parnassus and blue moor grass also occur. Adders frequent the site and the golden ringed dragonfly has been recorded. There are also a number of interesting freshwater species in the burn.
A narrow strip of grassland lies between blocks of conifer plantations. The Mill Burn runs through the centre of this strip with sections running over bare slabs of limestone, and the steep banks rise up to the forest edge on each side. An overhanging limestone outcrop occurs on a spur leading east from the reserve. There are occasional patches of willow and banks which are dominated by bracken - at the upstream end, the site is extremely wet. The site contains a diverse range of grassland types including limestone, mire and heath types. The site as a whole is fairly species-rich with an array of common and more unusual grassland and mire species. Notable species on the site include grasses of parnassus, blue moor-grass in patches along and near the burn, and common butterwort on the mire areas and burn edges. Early marsh-orchid occurs in a few locations in the site. Green spleenwort grows in sheltered locations on the limestone outcrops near the top of the site. Adders frequent the site and golden-ringed dragonfly occurs here. Grazing has been difficult but some areas are fenced specifically for this purpose.