Pollen Analytical Investigations at Holcroft Moss, Lancashire, and Lindow Moss, Cheshire

Abstract

Holcroft Moss, which lies 10 miles (16 km) west of Manchester to the west of Chat Moss at 75 ft (23 m) Ordnance Datum (O.D.), is about 1 mile (1.6 km) long and 3 mile (12 km) wide. It occupies several small depressions in the Upper Terrace of the Mersey Valley (Fig. lb). The north-east sector, which is uncut and used as a game covert, is covered by dominant Nardus stricta, Calluna vulgaris, Eriophorum vaginatum and Pteridium aquilinum with occasional Vaccinium oxycoccos and isolated Betula pubescens and Rhododendron ponticum. In the south-west sector, where most of the upper peat has been removed and only a small central table remains untouched, the vegetational communities are dominated by Molinia caerulea, Nardus stricta, Eriophorum vaginatum and E. angustifolium with occasional Calluna vulgaris. A levelled transect of drillings was constructed in a north-west direction across the north-east sector (Fig. 2). The basal surface consists of a thick layer of soft, unlaminated grey clay overlying boulder clay. Above the clay is a thin layer of Carex peat covered by an Equisetum peat rich in Menyanthes trifoliata seeds. This is succeeded by wood peat with frequent Alnus remains near the base and abundant Betula remains towards the top. The wood-peat is overlain by a highly humified Sphagnum-Calluna peat and is superseded by fresh Sphagnum imbricatum peat containing locally varying amounts of Eriophorum and Calluna remains. The peat transition is marked by a layer of pool peat rich in Sphagnum cuspidatum remains, Scheuchzeria palustris rhizomes, leaf sheaths and seedst and Menyanthes seeds. In the upper peat two distinct bands of highly humified peat are detected. Lindow Moss lies 12 miles (19 km) south of Manchester and 21 miles (4 km) northwest of the Keuper sandstone escarpment at Alderley Edge. This moss lies at about 200 ft (60 m) O.D. in two enclosed hollows within the boulder clay and glacial gravels, separated by a low ridge of sandy alluvium (Fig. ic). The disturbed top surface of the northern hollow, which is heavily drained, is covered by dominant Calluna vulgaris, Pteridium aquilinum and Festuca ovina with occasional Betula spp. and Pinus sylvestris. The plant communities of the southern hollow, which were undisturbed until early 1962,