IN 1851, William Kasten was shipwrecked off the headlands of Mendocino, Calif. HistoriI ans think he was on a silk schooner, but nobody knows for sure. Kasten, the first known white settler of Mendocino, left no diaries. The log cabin he was living in has disappeared, along with most of the lumber industry that made Mendocino a series of boom towns until the 1930s. As for the hippies who flocked there during the "Flower Power" era, most of them have gone, grown up or been accepted as town responsibilities. But now, as then, Mendocino County continues to attract pioneers, incorrigibles and dreamers. And for the traveler looking for the real California that existed before it turned into a series of branch outsets of I. Magnin, Mendocino County is probably California's last frontier.

The land lays itself out like a meditation: high cliffs, curved headlands, clumps of grazing sheep that turn cinnamon in the sunset. Everything is easy on the eye. Here and there a white-washed farmhouse, turning blue in the moonlight, sits on the edge of a meadow that drops off into the ocean. At night, the stars drop in your lap. Sea-weathered picket fences that long ago gave way to blackberry bushes, lean like crooked teeth over the highway. And with the sporadic exception of a "gypo" (independent) logging truck grinding its gears up an incline, Mendocino County--two hours north of San Francisco--is as silent as a redwood tree, or a marijuana grower.

Several years ago, Mendocino County achieved national prominence when a series of news stories revealed that the high-grade "sensemilla" pot was Mendocino's largest cash crop. "It's here all right," said Bill Zacha, owner of an art gallery in the town of Mendocino. "But they mostly grow it inland, where it's warmer." The streets of Mendocino are not exactly paved with pot.

The majority of the people in Mendocino County--which has an unemployment rate of 25 percent--are well-educated refugees from southern California who know how to create their own fall-back positions: Gestalt therapists deliver firewood, real estate agents bake bread. Zacha, a jackleg architect and professional artist who came to Mendocino in 1957, started out with a coin laundromat.

"I honestly don't know how we survived that first year" said Zacha. "My wife and I used to wait until the laundromat closed and then run down to scoop out the quarters for grocery money."

Survival is an issue in Mendocino County. Plumbing is poor, the climate is cold and whenever a storm slaps in from the Pacific, one can count on the electricity going out. But there are compensations. People can crank open their kitchen windows and pick wild blackberries for breakfast. The pace is humanly slow. And when the light slants through the redwood trees . . . Mendocino clears the mind.

If you follow the California smog north, it disappears forever around Cloverdale, the inland cut-off to Mendocino County. Rte. 128 takes you west through the apple and wine country of the Anderson Valley, winding through a picturesque swath of rural California into the redwoods that grow thick in the crevasses of the mountains. When small fists of fog start to punch your windshield, you are near the end of the labors--unless you encounter a flash flood of the Navarro River, a rock slide or a logging truck that has spilled its load across the center lane. One of the reasons Mendocino County remains almost as unspoiled as it was 100 years ago, is that getting there, despite the guidebooks htat cheerfully instruct you to take any number of routes, can be difficult. But persevere.

Once you arrive, you must reckon with Rte. 1. An endless roller coaster that climbs up mountain flanks, dips down to sea level (where driftwood is piled high on both sides of the highway), Rte. 1 is a series of switchback curves that rarely straighten out long enough for you to collect your wits. Then, too, most of us are used to taking our beauty in small doses. To round a corner and see ocean waves bouncing behind a stand of eucalyptus trees which have trapped the sun_like a tangerine_in its branches, is strong medicine for the uninitiated. But once there, Mendocino begins to work its magic as effortlessly as a seagull works the wind.

"People come here" said Mendocino native, Bill Matson, "because they find the total zero they've been looking for all their lives." Matson laughed. "And then, because there are no distractions, people become one with the zero."

Matson, who owns "The Greenwood Lodge" in Elk, contributes to the zeroing-in process by renting out small cottages with Franklin stoves, sitting rooms and deck-fronted bedrooms where guests can wake up and look at the ocean over breakfast, which Matson prepares and serves himself.

Innkeeping is a fine art on the Mendocino coastline. Once a series of small boom towns that fed redwood logs onto schooners that docked in the harbors, yesterday's redwood mansions (owned by logging executives) have been turned into today's tourist accommodations. And while it is perfectly possible to camp up and down the length of Mendocino County in a large number of state parks, you would have to be a charter member of the Sierra Club to turn down an opportunity to spend a night at the Harbor House Inn in Elk.

The rooms at the Harbor House look like they belonged to your rich aunt--the one with taste. The views from any window are full of nasturtiums, meadows or sea. And the food, seasoned with fog-watered herbs from the Inn's garden, is served in an ocean-view dining room overlooking the headlands. They say that at the posh Heritage House in Little River (where "Same Time Next Year" was filmed) guests read the Wall Street Journal instead of looking at the ocean. At the Harbor House Inn, the Wall Street Journal is available, but people forget to open it. Each inn has its own small differences, but it is hard to go wrong.

The best kind of traveling is probably undirected, but there isn't any way to discover Mendocino County without starting in the middle and then taking small trips north or south. Secure lodgings in the town of Mendocino, Little River or Elk, and then take excursions.

The town of Mendocino is the spiritual seat (Ukiah is the actual seat) of the county. For the real contemplatives, even Mendocino (pop. 1,170) is too urban. And the only reason anybody goes to Fort Bragg, 15 miles north, is for toothpaste and socks. But having never seen the entire country, I decided to drive north beyond both towns toward Leggett. I never got there. The road so terrified me that it was an enormous relief to dip down in the small hollow of Westport (pop. 100) and edge into the parking lot of "The Westport Deli."

The presiding figure at the "Westport Deli" is a wiry, no-nonsense woman called Thelma Marsh. Like most of the residents of the county, Marsh, who hails from Nevada, came to Mendocino from somewhere else.

A combination restaurant, lodge and gift shop--the kind your mother might operate out of her living room--the "Deli" is a hodge-podge of afghans, checkerboard carpet remnant flooring and rather compelling charcoal portraits of Martin Buber, an unnamed Tibetan monk and a mental patient in Sparks, Nev. The guest book is as eclectic as Marsh's art. "We get a lot of runaway wives," said Marsh, "and in the '60s when the hippies were around, they'd stop in on their way to Oregon. We'd give them food and clothing and sometimes their parents would write later on to say 'thanks.' "

The guest book at the "Westport Deli" is heavily laced with the names of guests from Sweden, Czechoslovakia and the Philippines. Westport is probably California's best kept secret but foreigners have discovered its charm.

Below Westport is Fort Bragg, which doesn't seem to know its own mind. If you stayed on the main street, you would be overwhelmed by "Gas 'n Grub" stations, fast food joints and doubtful looking motels. But there is more to Fort Bragg, once the thriving center of the Union Pacific Lumber Company, than meets the eye.

The "Grey Whale Inn" on Main Street used to be the lumber company hospital for employes. It still retains the wheelchair ramps between floors. The accommodations are large, well-furnished and light-struck. One is only a few blocks from the ocean. From an upstairs back room of the inn you can look down upon a patch of undisturbed Fort Bragg--small, nasturtium-clogged fences around redwood houses.

It is a short walk to The Johnson House Museum (formerly the official residence of the president of the Union Pacific lumber company) and to the Skunk Railroad, which used to transport logs. Today it transports tourists to day trips inland to Willetts through the redwood country.

On the south edge of Fort Bragg, beneath a bridge, is the small fishing community of Noyo. Small skiffs, bucking against incoming waves, head out to sea every day in search of bottom fish, abalone and crab. There are several seafood restaurants there and a fish-processing factory. You can also rent a boat to go fishing by yourself.

Continuing south the next town on Rte. 1 is Caspar. From the road, it looks like little more than a collection of chicken coops overlooking the Pacific. As they say in the real estate ads, Caspar "needs work." But look again.

The Caspar Inn is Mendocino County's hottest night spot, featuring live entertainment by name rock bands. At the other end of town is the McCornack Center for the Healing Arts. In a lush, enclosed garden setting, you can take accupressure treatments and yoga classes or spend an hour in the "Caspar Hot Tubs." There is something for everybody in Caspar, including a junk store called "The Mendo Surplus Plus."

The unincorporated town of Mendocino is organized enough to put out a brochure for visitors. On the back of the brochure it reads "WARNING: Never turn your back on the ocean!"

That would be difficult to do in any event.

The ocean constitutes one side of the main street, which is a cluster of art galleries, restaurants and gift shops, and you can mount the stairs to the second-floor outside balcony of Brannan's Restaurant and watch the whales spouting toward Baja California while you eat a hamburger.

Unlike Fort Bragg, the residents of Mendocino are fiercely protective of their village's character. Old-timers would just as soon tear down a flowerbox as look at it. But the sea-weathered, Victorian town with its broad streets, wild flowers jamming through fences and ivy-covered water towers (most of Mendocino County operates on individual wells) is naturally beautiful. Wander through the side streets, buy fruit at "The Corners of the Mouth" grocery that used to be an old church, take in the local museum and art galleries. Mendocino is full of artists, musicians and writers. The local bulletin boards will tell you whether there is a concert or play to attend while you are there.

Below Mendocino are the towns of Little River, Albion and Elk.. Each one of these towns has their assets. The travel brochures will tell you what they are. But it was Elk, where my mother, the pioneer, moved several years ago, where I spent most of my time. I had visited her in Elk once before this trip, but once was not enough.

According to the sign on the south edge of Elk, just below the abalone pickers' weekend cabin, the population is 270. Or, if you want to believe the sign on the north edge, across the street from the cemetery, the count is down to 251. Within this small button of a town are several fine inns, The Greenwood Pier Inn and Restaurant, the Green Dolphin Inn, the Greenwood Lodge and Harbor House. But there is more to do than eat and sleep in Elk.

Next to the Post Office is the "Force 10" ocean kayaking business, the only ocean white-water tour group in the country. Run by two strapping men in their twenties, Force 10 specializes in guided tours (you arelashed in a wetsuit in front of a guide onto a molded surfboard and taken out to explore the caves and caverns along the headlands. If you are really brave, "Force 10" guides will take you "storm skiing" on a specially designed ski, again with a guide behind..

The Elk Roadhouse probably offers the best and cheapest breakfast in Mendocino County. A no-nonsense little eatery, it is the meeting place for all the local ranchers, most of whom look as if they could throw a Mercedes off a cliff without taking off their jackets. Everybody (except you) knows who everybody else is.

The Elk beach, like all the beaches on the Mendocino coastline, is an undisturbed crescent piled high with driftwood. Behind the beach, the cliffs are covered with nasturtium vines so thick that one can climb, hand-over-hand, up the near-vertical cliffs back onto the road. Nasturtiums, even when they are not in bloom, smell strongly of honey. To lie upon a thick bed of green leaves on a sunny day watching sea gulls tread wind is a luxury that is free for the taking anywhere in Mendocino County. I took it in Elk.