About three years ago, my wife and I toured a few of California's national parks.

We had driven from San Diego through Baker to Death Valley, and to Sequoia, and were on our way to Yosemite National Park, driving east on Highway 140 from Mariposa.

We stopped at a barrier where the mountain had spilled tons of boulders across one side of the road, leaving only one lane open for a mile or more. From the looks of things, it was obvious that any attempt to clear the rocks from the road would only bring thousands more of them tumbling down the mountainside.

Cars and trucks rolled by us along the westbound side of 140; once they passed, a signal allowed cars in our lane to proceed.

The rocks stayed right where they were, teaching us a lesson: just because people had declared Yosemite Valley a park, that didn't mean nature was finished building it.

The naturalist John Muir, quoted in Ken Burns' imposing new documentary, "The National Parks: America's Best Idea," said it best: "One learns that the world, though made, is yet being made. That this is still the moment of creation, that mountains now conceived are yet being born." (Episode 1 of Burns' six-part, 12-hour project, called "The Scripture of Nature," airs at 8 p.m. Sunday, Sept. 27, on KPBS/Cable 11, repeating at 10 p.m. The rest of the episodes follow a similar schedule through the week.)

Burns, whose past masterpieces have included "The Civil War," "Jazz" and "Baseball," continues in his patented style, mixing film of awe-inspiring beauty - if you haven’t made the leap to high-def TV, this would be a good time to do so - with grainy historical stills and movies. Just a little warning, though: Burns was overly awed by his subject. His film plays too much like a civics lesson, as if he thinks you should watch it, out of respect, because it’s good for you. We visit national parks to have fun, not out of duty. Burns could have added some fun to his films.

He tells his story chronologically, beginning with men of the Mariposa Battallion who in the early 1850s stumbled into Yosemite Valley while looking for Indians, "intent on driving them from their homeland."

Only one of the men, to judge from their journals, took much notice of the grandeur of the place. It's always been like that, to judge from history as Burns teaches it. It hasn't always been obvious to everyone that the great places have to be preserved against humanity's worst instincts for everyone to enjoy. Even after Yosemite and Yellowstone were declared national parks, men found ways to exploit and despoil them, all in the name of "improvement."

It was prairie artist George Catlin who first suggested the idea of a national park, but nobody was listening. In 1864, while the Civil War was still being fought, Congress without controversy approved and President Lincoln signed a bill to give Yosemite to the state of California for the purpose of making it a public park. Already, Niagara Falls stood as an example of what was not wanted; every vantage point was owned by a commercial enterprise that charged fees for anyone who wanted to see the falls.

Burns tells his tale through the often-fascinating people who made the parks what they are, whether pioneering conservationist Muir; or James Mason Hutchings, a magazine publisher who first spread the word about the splendor of Yosemite and then decided he might as well profit from it; or John Colter, the mountain man who first told the nation about the boiling fountains of Yellowstone, only to be ridiculed as a loon, and the Nebraska couple who in the 1920s and 1930s traveled to as many parks as they could.

But judging by the broad, happy grin on his face, nobody enjoyed the parks more than President Franklin Roosevelt as he gazed on them from the rear seat of an open convertible.

As for Highway 140 into Yosemite, the rocks are still there, the road is still open only one lane at a time, and rangers say it will still be years before it's cleared.

----------------------

ABC this fall has brought us a raft of new series, some good, some not.

One of the most appealing is the comedy “Modern Family,” at 9 p.m. Wednesdays on KGTV/Channel 10.

For years, the knock on family comedies has been that they’re inevitably obsolete before opening night, that the American definition of “family” has stretched and splintered far beyond the traditional image of Mom, Dad, and 2.5 children. “Modern Family” meets and embraces the challenge and spins comedy gold from it.

The cast of characters includes one traditional couple with kids, one gay couple who just adopted a Vietnamese daughter, and one match of an older husband with a much younger wife who comes with a son from a previous marriage. The hook in this fractured domestic melody is that they’re all related in various ways, all members of a single extended family. The gay couple worry about acceptance, the dad worries his kids won’t think he’s cool, the older guy worries about connecting with his young stepson.

Ed O’Neill heads up a wonderful cast, writing and direction are just right, the laughs come along frequently. One of the season’s best.

“Cougar Town” airs right afterward at 9:30 p.m., and I can’t imagine a quicker, more disappointing letdown, witless where “Family” is witty, tasteless where “Family” is tasty, stale where “Family” is fresh and fabulous.

Courteney Cox stars as a just-divorced, middle-aged, extremely horny woman on the prowl for younger lovers. As far as the story goes, that’s about it. It’s a one-joke show, and the joke is told over and over with the finesse of a jackhammer ramming a hole in concrete. Listen for long, and you’ll think it’s your skull getting drilled.

ABC’s offerings this fall also include a new cop procedural from uber-producer Jerry Bruckheimer. And let’s give the man credit. He never wastes an idea. Sometimes one wishes he would, but he refuses.

"CSI," "Without a Trace" and "Cold Case," Bruckheimer shows on CBS, were all great ideas for cop shows. Then Bruckheimer tossed them into a blender and sold ABC his latest procedural, "The Forgotten.” Christian Slater stars as the leader of a troupe of Chicago volunteers who solve the murders of unidentified victims after the police give up. ("The Forgotten" airs at 10 p.m. Tuesdays, also on KGTV/Channel 10.)

The volunteers, whose relationship to the police is not exactly spelled out, call themselves "The Forgotten Network." They have jobs, but they don't seem to spend much time doing them. And judging from the pilot episode, they go about their mission pretty much as the police would, walking the neighborhood with a picture, asking if anybody recognizes this person.

So who needs 'em?