The 1861 Census has Grace Williams, age 3 (YoB 1858 born Porthmadog) but her obit. (Grace Roberts) in Yr Herald Cymraeg, 22 Apr 1919 doesn't give an age. However the GRO has a death registration Jun Qtr 1919 for a Grace Roberts, age 60, Festiniog (YoB 1859).
There is a GRO birth registration for a Grace Williams, Jun Qtr 1859, Festiniog, 11b 477 - mother's maiden name Jones.
Possibility?