To download free… 
“Cornwall” is a project developed by Timothy Ferguson – Proofreading by Mike and Salutor – Layout by me.
Here is the Introduction :
This gazetteer is a fan work, distributed with the kind permiss- ion of Atlas Games, who own Ars Magica. It is designed to be compatible with Heirs to Merlin: the Stonehenge Tribunal, the official supplement for England, and A Vanilla Covenant: The Covenant of Sabrina’s Rest, a fan work which covers the Severin Estuary and Bristol Channel, slightly to the north and east of Cornwall.
T. Ferguson
Here is the final version of “Mr Ferguson’s Cornwall” pdf written by Timothy Ferguson : Download it right now!