COUNTRYSIDE COUNCIL FOR WALES
SITE OF SPECIAL SCIENTIFIC INTEREST: CITATION
ANGLESEY CORS GOCH
National Grid Reference: SH497813
Site Area: 54.4 ha
Cors Goch is a nationally important valley mire developed in a hollow in Carboniferous Limestone. The geology is complex and interstratified with the limestone are beds of a coarse pebbly sandstone. In close proximity are found acidic heaths with heather Calluna vulgaris and pale dog-violet Viola lactea, limestone grassland with green-winged orchid Orchis morio and base rich fen. The fen is almost divided by a rock promontory into an east and a west basin. The east basin is very wet with an excellent association of 'brown mosses', black bog-rush Schoenus nigricans with sedges Carex spp and with communities dominated by great fen-sedge Cladium mariscus, common reed Phragmites australis and blunt-flowered rush Juncus subnodulosus. Higher areas in the fen have acidic vegetation with bog mosses Sphagnum papillosum and S. plumulosum. Around the margin bog-myrtle Myrica gale forms a zone with black bog-rush Schoenus nigricans. The western basin is somewhat drier, but contains similar fen communities, and a lake Llyn Cadarn, which has an interesting hydrosere with bulrush Typha latifolia common club-rush Schoenoplectus lacustris and water-Iilies Nymphaea alba and Nuphar lutea. The fen has a rich insect fauna, the Lepidoptera and Odonata being well represented.