O.C. POP MUSIC REVIEW : Abbey Rd. Spirit Lives On in Posies : The Seattle group displays superb songwriting, has a terrific lead guitarist and possesses the vitality of a garage band.

Midway through the Posies’ set Sunday night at the Coach House, singer/songwriters Jon Auer and Ken Stringfellow had a brief disagreement over whether their recent major-label debut “Dear 23”--with its multiplicity of muted album cover shades--should properly be referred to as “the blue album” or “the brown album.”

This allusion to the Beatles’ “white album” was in modest jest, natch, but such is this Seattle quartet’s unrecognized greatness that even in seriousness, such a nod would be far from heresy. The expansionist classic-pop spirit of “Abbey Road” is alive and well in the deliciously melody-driven Posies, along with a precociously clever lyrical maturity, a rambunctious garage-band spirit and, in Auer, a budding rock god of a lead guitarist.

“Dear 23” is as close to perfect as you’d want a pop album to get, and so the reasoned rough edges of Sunday’s show provided some welcome sloppiness, especially as the band trotted out some unfinished-sounding new material.

Still, as raw as they managed to be in moments, the Posies are unlikely to be confused with many of the other noisy outfits emanating from the far-left alternative Seattle scene--closer as they are to the Mamas and the Papas than Mudhoney in spirit and harmonies.

Their luscious “Apology” is a power ballad that puts the likes of Nelson to shame; sadly, it hasn’t even been released as a single, though word has it that it’s been No. 1 in heaven for about six months straight. Never mind the chilling, scissored insight of their crafty lyrics into all sorts of relational dysfunction--it’s virtually supernatural that they’re only in their early 20s.

Given their strengths as borderline-brilliant songwriters in the tradition of such teams as Lennon & McCartney and Difford & Tilbrook, their purely musical prowess was rather unexpected, with Auer’s very infrequent Hendrixian leads soulfully breaking up the power pop on rare stretches such as the slightly psychedelicized “Flood of Sunshine.” (Good thing he grew up in Seattle; in L.A., his nimble-fingeredness almost surely would’ve steered him toward a destiny in a less imaginative metal band.)

Also significantly, the drumming of Mike Musberger--who spends more time pounding on toms for dramatic effect than anyone this side of Keith Moon--put thunderous dynamics even in otherwise bubblegum-ish treatments.

Stringfellow, who fronts on about a third of the material, could certainly stand to project more; he frequently sang his emotive lyrics in the non-enunciating whisper of an apartment-dweller afraid to wake the neighbors. But from the Monkees-cum-Squeeze opener “My Big Mouth” to the hard-rock encore, Big Star’s “Feel,” this was your basic ‘60s-meets-’90s nirvana, unencumbered by undue slickness, slackness or attitude.

The Posies play tonight at Bogart’s in Long Beach and Wednesday at the Whisky in Hollywood.