It seemed, on the surface at least, a bit odd: Leon Russell touring the country a few years ago with the New Grass Revival. Had Russell, erstwhile ringmaster of Mad Dogs and Englishmen, turned stranger in a strange land, mixing the devil's music with the lonesome whine of bluegrass? Strange, indeed.

But not so strange to those already acquainted with the Revival -- as progressive and resourceful a band as bluegrass has to offer. Russell pops up again on the Revival's new album but just long enough to pump the piano some, and to help make one tune, "Nothing Wasted, Nothing Gained," sound like a southern rock anthem.

The rest of the album and its successes belong to the Revival. Somehow, the quartet has managed again to turn its principal weakness -- a lack of original material -- into one of its great strengths. There are some wonderfully vibrant and colorful cover versions here -- John Hall's "Reach," John Hartford's "Steam Powered Aereo Plane," Bruce Cockburn's "One Day I'll Walk," Bill Monroe's gospel number "Wicked Path of Sin" -- as well as more exotic fare, such as the Grismanesque "Sapporo." Throughout the album, John Cowan and Sam Bush sing with a vitality you seldom hear in bluegrass, let alone country music. And the exquisite blend of acoustic and electric instruments, highlighted by Bush's mastery of the mandolin, is often breathtaking.

Throw in the Revival's distinctive harmonies, rich and as smoothly appealing as those crafted by the Gatlin Brothers, and it's easy to understand why Russell, or anyone else for that matter, would want to play with them. They're that good.

For the more traditionally minded bluegrass fan, "Straight from the Heart" by local quintet Patent Pending revives the work of Bill Monroe, Ralph Stanley, the Louvins and others in a steady, workmanlike fashion. Mandolinist, singer and songwriter Eldred Hill is the one musician to watch. He's especially effective singing the simple yet often emotionally charged lyrics associated with the Stanleys. His own lyrics may not be a match for the Stanleys (i.e.: "It's not the faucet that you hear but the drippin' of my tears") or the Louvins ("You turned me away from the door of your heart") but the message is similar, and bassist Leigh Taylor's shadowy harmonies add a nice touch. ON RECORD, ON STAGE

THE ALBUMS: New Grass Revival, "Commonwealth" (Flying Fish FF254); Patent Pending, "Straight From the Heart" (Outlet Records STLP-1035).

THE SHOWS: New Grass Revival, Friday and Saturday at the Birchmere Patent Pending, Saturday at 9 at Tiffany Tavern, Alexandria.