NEWPORT, R.I. — Natalie Merchant's odd behavior was an extra, unexpected element of her appearance at the Newport Folk Festival as the de facto pop-crossover act on Sunday's bill.

The festival has depended in recent years on pop-crossover acts to fill the lawn chairs at big Fort Adams State Park. Folk-rockers Indigo Girls, perennial headliners in the '90s, filled that slot perfectly; they were also a potent draw for fans of the women's music movement.

On Sunday, the pop-crossover position on the Newport lineup fell to Merchant; the results were strangely mixed.

What does the former 10,000 Maniacs singer have in common with folk music? In her current show, plenty. Merchant is touring with a gifted, largely acoustic band, including fiddle, Dobro, acoustic guitar and, yes, even a banjo. More than half of her material Sunday was traditional folk songs and string-band tunes, including "Wayfaring Stranger," "House Carpenter" and "Sally Ann" (RealAudio excerpt of 10,000 Maniacs version).

Merchant's lonely vocals were appropriate to the plaintive songs, and the band at first sounded almost as Appalachian as the previous act, Peter Rowan.

Strange Days, Indeed

After a few songs, though, Merchant's eccentric stage patter took on a petulant air. It began with some innocuous flirting with the first rows of fans and some statements about how disgruntled she was with the whole idea of concert photographers. Then she began to make odd comments about the few festivalgoers who were leaving the park, though a thinning of the ranks at the end of a long festival day is hardly uncommon.

Soon she began complaining about the sound system and the microphone. Handed a new mic, she acted as if the attached cord was an impediment to her performance.

Merchant interrupted a single song several times, the melody tailing off into aimlessness. And then the singer proclaimed she didn't wish to be seen while singing.

"I don't like myself right now," she announced. "I think I'll sing the next song hiding behind the amp."

The audience was amused only at first.

"I wish she'd just sing the song already! I wanna dance," said Myra Binkley, 20, of Connecticut.

Merchant eventually settled down, yet her whole set, although musically accomplished, was a bizarre merging of folk sound and pop-diva performance style.

Merchant, in her late 30s, appears youthful, and her stage movements were rife with sensual undulations and wiggles — surprising behavior in the relatively sedate folk-festival setting. But it was intriguing to see pop-star charisma merged with ancient folk material. The slow, brooding take on "Sally Ann" was effective.

When it was time for "Cowboy Romance," Merchant began seated, wearing a small cowgirl hat. But when the tempo quickened and the drums kicked in, she flipped off the hat, jumped up and pranced about with cocky assurance.

Her most powerful song, however, was the highly political, pro-union chestnut "Which Side Are You On," a riveting rallying cry sung in dead earnest.

A Dose Of Reel Power and Gallantry

The rest of the day was blessed with one of the strongest Newport talent rosters in many years. Fiddle wizard Natalie MacMaster received the most fervent crowd reaction of the day, for her bravura Cape Breton reel-powered set.

Richard Shindell's gallant voice was made for a band, and the quartet he brought with him to Newport featured the nimble Larry Campbell, guitarist for Bob Dylan's band. Based on his festival performance, Shindell's confidence has grown during the year he spent with the ensemble Cry Cry Cry.

Dar Williams, another Cry Cry Cry graduate, appeared with a group powered by yet another gifted electric guitarist, Steuart Smith. Singing new songs from her soon-to-be released Green World CD in addition to plenty of sturdy songs from her earlier albums, Williams is a young star whose stage act has matured of late.

Much of the crowd seemed to be devoted Williams fans, mouthing the words to her songs "Iowa" (RealAudio excerpt), "When I Was a Boy" and "The End of Summer" (RealAudio excerpt). "As Cool As I Am," her wistful number about leaving a boyfriend with a wandering eye, has grown in concert, into an unlikely feminist anthem, with the line "I will not be afraid of women" eliciting a powerful response from the crowd.

Mary Gauthier, the New Orleans–bred songwriter, made an instant impression on the assembled 6,500. She's a tale-spinner with a great way with words, a wicked wit, a big heart and an intimate knowledge of Deep South eccentrics and lovable riffraff.

Thirty-five years after Dylan was booed for going electric at Newport, there was quite a collection of fine electric guitarists on hand. Mary Chapin Carpenter's effective, drummerless, stripped-down band featured the guitar play of Duke Levine and John Jennings.

Rowan Taps Into The Root

Nobody on Sunday's bill tapped into the soul of folk music more keenly than Rowan, whose Texas Trio featured bluegrass guitarist Tony Rice, bassist Bryn Davis and mandolinist Billy Bright. From his hippie anthem "Panama Red" to a noble rendition of "Shackles and Chains," Rowan and his band dug into a timeless vision of the American spirit. On "The Land of the Navajo," Rowan wailed, caterwauled and yodeled with the power of an entire tribe touched by peyote.

Rowan recalled the time he was with the legendary Bill Monroe, back when he was a very young member of the Bluegrass Boys.

"It was in 1964, and we were broke down on the road, in the Midwest, on the way to play the Newport Folk Festival. We sat down by the side of the road and wrote this song," Rowan said. The song was the classic "Walls of Time" (RealAudio excerpt), and Rowan's rendition at Newport on Sunday was laced with haunting harmonies.