331. Admissibility of extrinsic evidence.

Extrinsic evidence is admissible of all objective material facts existing at the time of execution of the deed which were reasonably available to the parties at the relevant date, as part and parcel of the process of contextual construction1. Extrinsic evidence is not admissible to contradict, vary or add to the terms of a deed2 but only to put before the court the same knowledge of the subject matter of the deed as was in the possession of the parties to it at the time of its execution3. It may also be admitted where the description of the boundaries