What crucial element moved the Tenterfield from being a cross to a distinct breed?

Answer

Consistent application of breeding standards within the Tenterfield region

The crucial element was the geographical isolation combined with the consistent application of breeding standards within the Tenterfield region, which selected for conformity in appearance, gait, and temperament.

What crucial element moved the Tenterfield from being a cross to a distinct breed?
OriginDogtypebreedTerrier