California Code, Public Resources Code - PRC § 5868

(1) Illustrative character, which requires the property to exhibit a combination of well-developed components that are recognized in the appropriate scientific literature as characteristic of a particular type of natural feature.  Generally, the property should be unusually illustrative, rather than merely statistically representative.

(2) Present conditions, which require that the integrity of the significant features of the property has been maintained, enhanced, or restored.

(1) Diversity, which requires property, in addition to its primary natural feature, to contain high quality examples of other biological or geological features or processes.

(2) Rarity, which requires property, in addition to its primary natural feature, to contain rare geological or paleontological features or natural communities, or to provide high quality habitat for one or more rare, threatened, or endangered species.

(3) Value for science and education, which requires the property to contain known or potential information as a result of its association with a significant scientific discovery, concept, or exceptionally extensive and long-term record of onsite research, with the result that the property offers unusual opportunity for public interpretation of the natural history of the state.