Old Saint Hilary's Open Space Preserve

[4] The presence of Serpentine, which is the state rock of California, creates a unique soil composition and can be found in other parts of Marin.

[5] The peculiar geology and freshwater springs in the area provide a distinct ecosystem, giving rise to unique species.

[7] According to a recent study, the Open Space land used to be continuous with nearby areas, all of which was the habitat of the Tiburon Jewelflower.

Also, gene samples which compare the current groups to the older one (saved in a seed bank) indicate an overall loss of genetic diversity.

However, it is still vulnerable to another hazard: hikers going off trail which "could destroy the new seedlings", despite signs posted by the Marin County Department of Parks and Open Space that prohibit this activity.

[10] As part of a public health measure in the 1930s, the Works Progress Administration constructed an outhouse for Old St. Hilary's Church.