1. Llyn Cau National Nature Reserve. 'The reserve encompasses the mountain and lower slopes, with a variety of habitats of European importance. These include dry heath, wet heath, blanket bog, woodland and the species-rich marshy grasslands of Tir Stent common, as well as a number of low nutrient or clear-water lakes. The cliffs support tall herbs growing on the ledges, and a range of plants growing on rock crevices. These habitats support a wide range of species, including slender green feather-moss and marsh fritillary Butterfly'. Source: http://www.visitmidwales.co.uk/Dolgellau-Cadair-Idris-Nature-Reserve/details/?dms=3&feature=5&venue=1012055

2. There is a high likelihood that the lake was a place of sacred importance in the Iron Age given the find of a hoard of La Tene Late Iron Age metalwork (NPRN 419531) a kilometre to the south-east on the mountain path up to the lake. However, further archaeological investigation of the landscape environs of the lake are required to place it in a more robust archaeological context.

T. Driver, RCAHMW, 9th Oct 2018.