Visiting our coast

A Sea Ranch geologist points out the interesting natural highlights along the coastline.|

The coastal region of Sonoma and Mendocino counties rivals any other area along California’s 840-mile coastline for sheer beauty as well as geologic intrigue. For a daytrip, you’ll only be able to see a small part of it. But do wade in and relish our local delights.

Here are some ideas for a short visit along the Sonoma County coast. In light of the need to avoid crowds during the coronavirus pandemic, these outings are ideal for a couple, family or individual. Parking is open in many areas, but do check parks’ websites for the latest information. And remember to social distance and wear a mask when encountering others, as is required in all of these locations.

Bodega Bay

Bodega Bay offers a variety of adventures. Just north of town at Salmon Beach is a favorite spot for surfers. The beach is long, the bluff-edge parking is close and there are no pesky rocks to avoid.

Just to the north you can see wonderful sea stacks rising out of the ocean. As their name implies, sea stacks are large stacks of rock resembling tall stone towers. The offshore stacks still are being formed by wave action; they’re made of slightly harder rock than the surrounding rock, and erosion occurs around them. On the lower coastal terrace, also cut by wave action 81,000 years ago, you will see fossil sea stacks protruding above the terrace. Many marvelous small coves here give shelter from the wind and a chance to explore these interesting nooks and crannies up close.

While here, visit Bodega Head, which juts into the ocean. The underlying granite was formed by the melting of the Pacific plate as it plunged down into the mantle of the Earth. Later, the plate was lifted to the surface. Granite is not seen north of here as that area is covered by Cretaceous and Tertiary sedimentary rocks.

Sand dunes also partially cover the granite and hiking trails which ring the Head. It’s best to visit these trails early in the morning or during a season of low wind. The two most windy spots along the coast are Bodega Head and the Point Arena Lighthouse. A good jacket or hooded sweatshirt are smart choices to have on hand, even during summertime. For Bodega Bay, there’s day use parking at Salmon Creek ($8).

Just to the south, looking into the Bay, is a short trail to the “hole in the head,” which now contains a small pond. This was the site PG&E planned to use for a nuclear electric generating plant in the 1960s. Imagine it! The San Andreas fault is just 1,000 feet east, on the other side of the bay. Nuclear power plants need water for cooling. Think of the environmental effects of discharging hot water into Bodega Bay, not to mention the dangers of fault movements or possible tsunamis. The project became a rallying point for much of California’s burgeoning environmental movement at the time. The California Coastal Act and the Coastal Commission were formed to stop this kind of development.

If you can, stay for sunset. Have you ever seen the “green flash?” It’s a rare phenomenon that happens when visibility conditions are just right; it can only be glimpsed for a few seconds as the sun makes its final descent. There’s a noticeable burst of green light at the horizon as the density of the air directly over the ocean gives a prism-like effect to the slanting rays of the sun. Obviously a challenge to photograph!


Jenner is a second choice for a day visit. It’s a quiet, sleepy little village with minimal facilities. The mouth of the Russian River is here, with a long sandy bar. More than 200 harbor seals claim the beach daily at low tide. At high tide, you may see a few, but the rest usually have gone fishing. You can drive to the beach from the Goat Rock entrance just to the south and up the hill from the bridge. This is one of the few places where you can park almost right on the beach in a large parking lot. As Goat Rock is a protected home for the seals, no dogs are allowed on this beach.

Jenner Headlands Preserve is 1.5 miles north of Jenner off Highway 1. Over 5,600 acres primarily east of the highway rise up the hillside and over the ridge into forest lands. The preserve features 14 miles of trails including an ADA-compliant trail. Climbing the steep western slope provides splendid views of the coast and river mouth. According to the preserve’s website, visitors from outside the local area are asked not to visit currently ( But the preserve and parking are free. Open daily from 8 a.m. to sunset. There is no water available, so bring your own. Dogs are welcome if leashed.

If you picked the wrong day and the wind is high on the Russian River bay mouth bar, you might swing back inland to Guerneville and visit Armstrong Woods State Natural Reserve. Trails and picnic spots are plentiful in the park. The old-growth redwoods are amazing. Fire scars mar the trunks quite far up in places. This fire reportedly occurred in the 1940s. Even small trees seem to have survived. Some 80 years later, one would suspect these small trees would be larger in diameter, so perhaps their growth was indeed stunted by the fire. But there are large magnificent trees all around. Redwoods don’t become a climax tree until they are more than 1,000 years old.

Farther north

Salt Point State Park contains over 6,000 acres of coastline and adjacent forests and there are over 20 miles of trails inside the park. The park’s name refers to the rock cavities, called tafoni, where the salt from ocean water crystallizes in honeycomb-like crevices. There are several entrances and small coves along the length of the park.

Coves all along our coast are formed by multiple faults, which cause the rocks to dip in different directions, to a geologist’s delight. There’s also an underwater park, picnicking, horseback riding, fishing, diving and camping. It’s a favorite place for gathering wild mushrooms and for abalone picking. The park is open daily from sunrise to sunset. Picnic areas are currently closed.

Kruse Rhododendron State Natural Preserve is adjacent with Kruse Ranch Road (dirt) cutting through the reserve itself. The flower bloom starts in late April and lasts a couple of weeks. Timber Cove and Fort Ross are just south along Highway 1. The reconstructed Fort Ross gives us a glimpse into the past as this was the hub of the southernmost Russian settlements in North America during the early 1800s. While the fort’s museum is closed due to the pandemic, the Fort Ross grounds and the visitors center are open, along with the coastal trails. Day use parking is $8.

The San Andreas fault comes back on land just south of Fort Ross at highway milepost SON 30.30. The adjacent streams just to the east of the fort are offset by the fault movements in four different spots. You can note some of these effects by driving east on Fort Ross Road where you’ll see a gully to the right that trends to the west. The stream then turns abruptly south near the junction with Highway 1. This sudden, sharp right angle is the result of the offset on the two sides of the fault. If you stop at the sign to Stanley S. Spyra Memorial Grove and take the trail to the north, you’ll see the other fault features — broken tree tops, split trunks and several sag ponds. A sag pond occurs next to a fault and often has a small hill next to it (a pressure ridge).

Picking wild mushrooms in the park is a favorite activity for many people. At the north end is one of my favorite spots for watching big waves as they roll, crash and send white spray shooting skyward. Horseshoe Point catches the waves at a perfect angle, amplifying their dramatic thundering.

The Sea Ranch stretches along 10 miles of coast at the northern edge of Sonoma County. Although a private seaside community, it has five public beach access points with parking for 10 cars in each parking lot adjacent to Highway 1. There are nearly 6 miles of trails for visitors.

In visiting one or more of these spots, you may find your own personal gems, but you won’t do so unless you leave the city behind. Sit down somewhere and quietly wait. Many critters won’t reveal themselves for 20 minutes or more. Once I watched a blue heron for 45 minutes. It stood perfectly still, waiting patiently for a gopher it had spotted. Gopher holes are everywhere. After 45 minutes, my attention was diverted elsewhere. I saw birds circling, whales blowing while trekking by on their coastal migration route and a lizard scampering over the sand. Then zap! I almost missed it. The heron struck the gopher as he emerged from his hiding spot and I saw the bulge gulp down the heron’s throat.

Happy trails, folks. There is much to see and learn, and both visitors as well as locals should fully relish our majestic-albeit-fragile coast.

Thomas E. Cochrane is a California Professional Geologist and Sea Ranch resident who has been prowling the landscape of Sonoma and Mendocino counties since 1976. He’s a guest speaker for organizations such as the Sonoma Land Trust and author of three books, including “Shaping the Sonoma-Mendocino Coast — Exploring the Coastal Geology of Northern California.” To learn more:

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