You're spot on Jack, it is the Sundial at St Beuno's Church in Clynnog Fawr, The other photo is of the well there.

The sundial probably dates to the 10th or 11th century. It was for many years used as a footbridge across the Glan-Mor mill stream at Aberdesach. It was later used to support milk pails at Llyngele Farm. It was returned to Clynnog Fawr churchyard in 1930. The sundial face is eched with three lines, dividing a semicircle into four parts, the traditional method used in Saxon time to divide each 24 hour period into 8 equal parts, or tides.