Though these terms are new to me I'll throw in my 2 cents as to where the lines would be drawn.
I'd agree with the others about 1st generation being the originators Bill Monroe, Flatt and Scruggs, etc. These guys kicked up the old-timey sound to have a very strong drive and beat in much the way rock and roll sprung from blues.
The 2nd generation would be the bands that expanded the music to include more complex or folky songs with more chords and harmonies and such. This would include the Country Gentleman, Kentucky Colonels, Seldom Scene, the New South.
3rd generation would be the bands that added longer jams and more complex rhythms to the sound. This includes New Grass Revival, David Grisman Quintet, and the more recent Jamgrass bands like String Cheese Incident and Leftover Salmon.
I'd agree with the others about 1st generation being the originators Bill Monroe, Flatt and Scruggs, etc. These guys kicked up the old-timey sound to have a very strong drive and beat in much the way rock and roll sprung from blues.
The 2nd generation would be the bands that expanded the music to include more complex or folky songs with more chords and harmonies and such. This would include the Country Gentleman, Kentucky Colonels, Seldom Scene, the New South.
3rd generation would be the bands that added longer jams and more complex rhythms to the sound. This includes New Grass Revival, David Grisman Quintet, and the more recent Jamgrass bands like String Cheese Incident and Leftover Salmon.