Vertical cliffs hit the water and plummet through forests of California hydrocoral, another testament to the health of these waters. Undisturbed by river runoff, the water here is exceptionally clear and Mother Nature has even thrown in a few shipwrecks for fun. About one-half mile offshore of Yankee Point is a massive underwater mountain. What at first seems a flat plateau is actually a massive granite structure, deeply scored with branching canyons and valleys. Colorful sponges, Corynactis anemones and coralline algae cover nearly every rock surface and seem to leave little room for the hordes of sea stars and large rose anemones.
Game fish hide among the palm kelp and rocky crevices.
Orange sea cucumbers and rock scallops nestle in cracks, and chestnut cowries, rare in most of north-central California, are plentiful here. This dive is a charter boat favorite, but advanced divers can reach the rocks from shore. Divers attempting this should be accustomed to rugged, strenuous conditions. This is an unforgiving piece of coastline. The Diablo Pinnacles , a pair of rocks that reach up from a 100-foot bottom to just below the surface, can be dived only from a boat.