What constitutes adverse possession under claim of title not founded on written instrument.

NRS 11.140 What constitutes adverse possession under claim of title not founded on written instrument. For the purpose of constituting an adverse possession, by a person claiming title, not founded upon a written instrument, judgment or decree, land shall be deemed to have been possessed and occupied in the following cases only: 1. Where it has been protected by a substantial enclosure. 2. Where it has been usually cultivated or improved. [1911 CPA § 17; RL § 4959; NCL § 8516]