Strawberry Spit (also Sanctuary Island) is a small artificial island in the

San Francisco Bay San Francisco Bay is a large tidal estuary in the U.S. state of California, and gives its name to the San Francisco Bay Area. It is dominated by the big cities of San Francisco, San Jose, and Oakland. San Francisco Bay drains water from a ...

Richardson's Bay Richardson Bay (originally Richardson's Bay) is a shallow, ecologically rich arm of San Francisco Bay, managed under a Joint Powers Agency of four northern California cities. The Richardson Bay Sanctuary was acquired in the early 1960s by the Nat ...

embayment A bay is a recessed, coastal body of water that directly connects to a larger main body of water, such as an ocean, a lake, or another bay. A large bay is usually called a gulf, sea, sound, or bight. A cove is a small, circular bay with a narr ...

of Strawberry Lagoon. It is still referred to as Strawberry Spit, although it no longer is technically a spit. Historically the spit was a haul out area for

harbor seal The harbor (or harbour) seal (''Phoca vitulina''), also known as the common seal, is a true seal found along temperate and Arctic marine coastlines of the Northern Hemisphere. The most widely distributed species of pinniped (walruses, eared sea ...

s. A channel was built separating Aramburu Island from the mainland to isolate and therefore protect the seals from human disturbances. The landscape north and landward of Strawberry Spit is dominated by Ring Mountain, whose slopes are strewn with a multitude of boulders that include minerals such as

mica Micas ( ) are a group of silicate minerals whose outstanding physical characteristic is that individual mica crystals can easily be split into extremely thin elastic plates. This characteristic is described as perfect basal cleavage. Mica is ...

amphibolite Amphibolite () is a metamorphic rock that contains amphibole, especially hornblende and actinolite, as well as plagioclase feldspar, but with little or no quartz. It is typically dark-colored and dense, with a weakly foliated or schistose (flaky ...

and

eclogite Eclogite () is a metamorphic rock containing garnet (almandine-pyrope) hosted in a matrix of sodium-rich pyroxene (omphacite). Accessory minerals include kyanite, rutile, quartz, lawsonite, coesite, amphibole, phengite, paragonite, zoisite, dol ...

.C. Michael Hogan (2008) ''Ring Mountain'', The Megalithic Portal, ed. Andy Burnha

References

Islands of San Francisco Bay Islands of Northern California Islands of Marin County, California Mill Valley, California {{MarinCountyCA-geo-stub

See also

References