Original sentence: Further remnants of Neolithic habitation were uncovered in 1880 when an ancient settlement was discovered by Thomas Plunkett in 1881 beneath the surface of a peat bog (the coal bog)
Edited sentence: Further remnants of Neolithic habitation were uncovered in 1880 when an ancient settlement was discovered by Thomas Plunkett in 1881,  beneath the surface of a peat bog (the coal bog)