WIKIPEDIA:

“ New Grass Revival was an American progressive bluegrass band founded in 1971, and composed of Sam Bush, Courtney Johnson, Ebo Walker, Curtis Burch, Butch Robins, John Cowan, Béla Fleck and Pat Flynn. They were active between 1971 and 1989, releasing more than twenty albums as well as six singles. Their highest-charting single is "Callin' Baton Rouge", which peaked at #37 on the U.S. country charts in 1989 and was a Top 5 country hit for Garth Brooks five years later.

Early years
The origins of New Grass Revival lay in the Bluegrass Alliance, which Sam Bush (vocals, fiddle, guitar, mandolin) and Courtney Johnson (banjo, vocals) joined in 1970. At the time, the Alliance also featured bassist Ebo Walker and fiddler Lonnie Peerce. Within a year after Bush's and Johnson's arrival, Curtis Burch (dobro, guitar, vocals) joined the band. In 1972, Peerce left the band, and the remaining members decided to continue under a new name—New Grass Revival. The band released their eponymous debut, Arrival of the New Grass Revival, later that year on Starday Records.

Separation from mainstream bluegrass
Other groups were also playing progressive bluegrass at the time, such as The Dillards, Eddie Adcock's II Generation, and the Country Gentlemen, but few did [......] ”

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