Allt Wen Slate Quarry is a putative site believed to lie concealed in woodland/forestry on the eastern edge of Llyn Padarn. A quarry feature is portrayed on the Ordnance Survey first-edition map of 1889 and annotated as 'Old Quarry' on the second-edition map (Caernarvonshire sheet XVI.8)
Source: A.J.Richards, A Gazeteer of the Welsh Slate Industry (1991), p.30.
