Visitors 57
Modified 6-May-26
Created 3-May-26
29 photos
Ring Mountain is a jewel. Identified by the Nature Conservancy as one of California’s Critical Areas (representing the serpentine ecosystem), it holds rare and ultra-rare plants in addition to classic serpentine-loving natives. Exposed rocks and boulders testify to its tortured geological heritage.
We had the ideal guide: Lynn Lozier. In her long tenure at TNC, she was involved with Ring Mountain from the beginning, becoming the preserve’s first manager and overseeing its transfer to Marin County Parks. She filled us in on the tortuous history of Franciscan mélange, cobbled together from many rock types, mixed and stirred, scraped off the Continental Plate as the Pacific Plate ground underneath. The literal high point of the tour was Turtle Rock – Franciscan mélange covered in colorful lichen -- with long views of the preserve, the Bay, and beyond.
Serpentine rock is different: seafloor sediment from the Pacific Plate, transported deep below to experience extreme pressures at surprisingly low temperatures and in the presence of water, squeezed upwards along geological faults, exposed by erosion on hilltops. Shy in essential plant nutrients such as calcium, nitrogen, phosphorus, and potassium, heavy in magnesium and difficult heavy metals including chromium, iron, cobalt, and nickel, serpentine soils are a challenge to plant life. Over the eons, many native plants have mastered this challenge. Invasives, including the European grasses, still have a hard time –serpentine soils tend to be refuges of California native plants.
Serpentine rock is the California State Rock; it occurs many places in California, especially along the plate boundaries. Ring Mountain has some plants even rare in California serpentine elsewhere. We saw Marin Dwarf Flax (Hesoerolinon congestum). Listed as threatened by the US and California, it occurs only on the Peninsula and in Marin County, in perhaps 20 limited locations. (Toni Corelli found some at Edgewood Park.) Ring Mountain is the primary location managed to preserve this rare plant.
The most rare plant we saw was the Tiburon Mariposa Lily (Calochortus tiburonensis). Known to Western science only since 1971, it has been found only on Ring Mountain despite an extensive search in similar ecosystems. It is blooming late this crazy year; we saw its single, singular leaf and some buds.
Lynn also told us a little of the tortuous path that led to preservation of this prominent property. In 1980 the Nature Conservancy launched their California Critical Areas Program, which identified optimal examples of our unique ecosystems and worked for their preservation. Ring Mountain was chosen as the quintessential serpentine ecosystem. The road to its preservation was tortuous and rocky; the land was assembled piece by piece as opportunity presented. Lynn managed the preserve. They made the boundaries more secure or at least known, cleared trash, planned and built trails, and shepherded the land. In 1995 TNC transferred ownership to the newly-formed Marin County Open Space District – keeping a conservation easement. TNC continues to support its operation.
Kurt Rademacher, also retired from TNC, added his botanical insights for us, and remembered working with my nephew Charlie Quinn.
Nice outing, nice company, nice landscape. I learned a lot.
Click on a photo to see it in full, and to read the caption. Please post a comment to the photo if you have a correction or anything to add.
We had the ideal guide: Lynn Lozier. In her long tenure at TNC, she was involved with Ring Mountain from the beginning, becoming the preserve’s first manager and overseeing its transfer to Marin County Parks. She filled us in on the tortuous history of Franciscan mélange, cobbled together from many rock types, mixed and stirred, scraped off the Continental Plate as the Pacific Plate ground underneath. The literal high point of the tour was Turtle Rock – Franciscan mélange covered in colorful lichen -- with long views of the preserve, the Bay, and beyond.
Serpentine rock is different: seafloor sediment from the Pacific Plate, transported deep below to experience extreme pressures at surprisingly low temperatures and in the presence of water, squeezed upwards along geological faults, exposed by erosion on hilltops. Shy in essential plant nutrients such as calcium, nitrogen, phosphorus, and potassium, heavy in magnesium and difficult heavy metals including chromium, iron, cobalt, and nickel, serpentine soils are a challenge to plant life. Over the eons, many native plants have mastered this challenge. Invasives, including the European grasses, still have a hard time –serpentine soils tend to be refuges of California native plants.
Serpentine rock is the California State Rock; it occurs many places in California, especially along the plate boundaries. Ring Mountain has some plants even rare in California serpentine elsewhere. We saw Marin Dwarf Flax (Hesoerolinon congestum). Listed as threatened by the US and California, it occurs only on the Peninsula and in Marin County, in perhaps 20 limited locations. (Toni Corelli found some at Edgewood Park.) Ring Mountain is the primary location managed to preserve this rare plant.
The most rare plant we saw was the Tiburon Mariposa Lily (Calochortus tiburonensis). Known to Western science only since 1971, it has been found only on Ring Mountain despite an extensive search in similar ecosystems. It is blooming late this crazy year; we saw its single, singular leaf and some buds.
Lynn also told us a little of the tortuous path that led to preservation of this prominent property. In 1980 the Nature Conservancy launched their California Critical Areas Program, which identified optimal examples of our unique ecosystems and worked for their preservation. Ring Mountain was chosen as the quintessential serpentine ecosystem. The road to its preservation was tortuous and rocky; the land was assembled piece by piece as opportunity presented. Lynn managed the preserve. They made the boundaries more secure or at least known, cleared trash, planned and built trails, and shepherded the land. In 1995 TNC transferred ownership to the newly-formed Marin County Open Space District – keeping a conservation easement. TNC continues to support its operation.
Kurt Rademacher, also retired from TNC, added his botanical insights for us, and remembered working with my nephew Charlie Quinn.
Nice outing, nice company, nice landscape. I learned a lot.
Click on a photo to see it in full, and to read the caption. Please post a comment to the photo if you have a correction or anything to add.
Dan Quinn