Found some more on this. again from the Manx notebook

Thorkel Farmland. The land was south of the road running from the ford in the Santan Burn river west to Ballasalla and probably went south to the coastline. The boundary line ran from the ford in the river at that time called the river Coma along the highway between the Thorkel farm, (otherwise Kyrke Mychell) and Herinstad. The line then passes along a wall which is the limit between the above mentioned Thorkel’s Estate and Ballasallach. It then descends from Ballasallach along a wall and ditch to the river Russin and along the river to Castle Russin.