This seems to be a high round cairn with a long barrow protruding from it, according to the professional opinion (thanks Irene!). It sits in a field by the farm of Kilmorich, quite near to an old well, but isn't marked on any maps, or noted anywhere that I've seen.
Directions - head N on the A9 from Perth. About 9km after Dunkeld, take the (very small) road to the right for Guay. The cairn and barrow are on the right of the road about 2.5km further on, opposite the memorial on the left-hand side.