Possible Quern Stone
The stone was found at the Promontory Site described in trove.scot ID 360740 which is located at National Grid Reference NS 73512 52955.
The 3-maps location is

Excavation Site in the local coordinate system

Photos of Quern stone in trench T10

Quern Stone circled at top left 
Discussion
The possible quern stone was found buried inside a possible structure marked by the large flat stones in the above photograph. Other finds on the site suggest an Iron Age date with similarities to the Castle Qua site beside Lanark. It may be that the possible structure was an Iron Age house and that the stone was buried inside it.
