Sadly, the Jayhawks have flown off into the pop-folk horizon, leaving behind several extraordinary albums.

But it doesn’t entirely end there.

Guitarists Gary Louris and Marc Perlman are teaming with fellow ex-‘Hawks Karen Grotberg (keyboards) and Tim O’Reagan (drums) for a still-unnamed outfit, going into the studio in March to record an American Recordings album.

More immediately, Louris and Perlman are part of an alternative supergroup called Golden Smog, collaborating with Dan Murphy of Soul Asylum, Kraig Johnson (formerly of Run Westy Run), Wilco’s Jeff Tweedy and Minneapolis drummer Noah Levy . They make their Rykodisc debut with the unpretentious full-length LP, “Down By the Old Mainstream.”

Louris call it’s a musical love-in.

“It’s a big fat wet kiss,” he said recently. “It’s Dinosaur Jr. meets the Stanley Brothers meets cheap Rolling Stones. It’s really bizarre. Everyone’s got their own writing style, and it all kind of magically works.

“For some reason, I would not play somewhere and Dan would play guitar that would fit in just perfect. Somehow it all works … it’s a really unusual blend.”

Nearly a year in the making (and waiting for the legal fog to settle), the Golden Smog effort allows each member to experiment, testing new waters that their previous or current bands could not afford.

“You let go a bit more because it’s not supposed to be serious,” Louris said. “We used to be a joke band. We played every six months because we knew we could make a lot of money and we didn’t have to practice twice.

“We play in Minneapolis and play a lot of bad covers. We started off as Exile On Lake Street, a Rolling Stones cover band. Then we evolved into Golden Smog, which meant we could basically play any cover. We’d play things like ‘The Most Beautiful Girl in the World’ by Charlie Rich, ‘Spooky’ and then some Bread song, and we’d do ‘Wildfire’ and Aerosmith’s ‘Kings & Queens.’ We really mixed it up, from Waylon Jennings to The Clash.”

Then somewhere along the line, Golden Smog became larger than life.

“One day we realized that we could actually be a really good band because we had a lot of songs that we didn’t have outlets for,” Louris said. “Mark, for instance, didn’t get a good many of his songs on Jayhawks record, but he’s a good songwriter. Dan Murphy doesn’t get to do enough on Soul Asylum records than maybe he should. This time he gets a chance to do that.”

Among the highlights are the Louris/Tweedy collaboration “Radio King,” Tweedy’s witty “Pecan Pie” and the stunning “Nowhere Bound,” featuring the guest vocals of Soul Asylum’s Dave Pirner.

Because each Smog member is on different labels and has contractual obligations, they have assumed pseudonyms. Louris isn’t sweating the small stuff.

“This is what music’s all about,” he said. “This is why I got into the music business in the first place. We’re having a great time, and no one in a three-piece suit can tell us otherwise.”

BWF (before we forget): The Jayhawks, led by Gary Louris, reappeared in 1997 with the American Recordings album “Sound of Lies.”