Aside from their shared roots in the soil of American vernacular music, what these new discs have in common is that neither lasts to full length. In fact, these EP (extended play) recordings together comprise 11 cuts and 39 minutes, about the duration of an average CD. EPs are generally meant to provide a small taste of what an artist has to offer or is working on currently.

The daughter of oldtime banjo/fiddle master Dan Gellert, Rayna Gellert has established a name for herself as a member of the defunct all-female stringband Uncle Earl, which released a couple of first-rate albums for Rounder in 2005 and 2007. To those of us who worried about it, Uncle Earl provided assurance that traditional music would survive and thrive in the new century. Member Abigail Washburn went on to establish a high-profile career on the roots scene. Gellert has been involved in various projects since then, but since I don't get to hear everything I want to hear, they are unfamiliar to me.

Workin's Too Hard makes me wish (1) I had heard them and (2) this were rather longer than 24 minutes. Then again, where the latter is concerned, it's entirely possible that these seven cuts -- two traditional, five original -- were the sum total of what Gellert felt prepared to release; anything else, at this moment anyway, would have been inferior or superfluous. Whatever the reason, this turns out to be a most enjoyable outing. Gellert sing and plays (fiddle, guitars) backed by a three-piece band, including Kieran Kane, the folk- and bluegrass-oriented Nashville singer-songwriter. Workin' highlights songwriting on a Jean Ritchie level, and no higher praise can be spoken.

Kane and Gellert collaborated on "River Town," the loveliest newly composed number I have heard so far in 2017. Gellert's voice couldn't be more perfectly tuned to this old-sounding song of ambivalent reflection on a marriage that managed to endure even as it didn't turn out as happily as promised. "River Town" will be there spinning inside your head long after your player is silent. Old folk music endears itself to me most of all for its emotional depth. You don't hear it often even in the best new folk music, but it is here, and at full strength. Though "River Town" stands out, her other originals, drenched in the melancholy vocabulary of rural music, are hardly less striking. Indeed, they feel powerful enough to stop time.

Her handling of the venerable "Oh Lovin' Babe" touches the heart, too, not only because it's a fine choice but because of a creative arrangement that yet gives off the impression it had been with the song ever since it was first set to flight in some misty past. I am not quite so enthralled with the rocked-up version of the 19th-century hymn "I Am Bound for the Promised Land," probably because I am so fond of it done as it was in the days of the oldtime religion. I expect I'll grow into it, though.

I know the Revelers from their full-length CDs issued in recent years. Formed by members of two acclaimed neo-traditional Cajun outfits, the Red Stick Ramblers and the Pine Leaf Boys, the band plays, as advertised, the distinctive Louisiana rock 'n' roll known as swamp pop. The genre fuses older sounds (represented here by accordion and fiddle) with mid-century country, r&b and rockabilly.

Well, a lot of recorded history attests that you can't go wrong with that particular combination, and the six Revelers do it all right in every way. Performing songs from Gary U.S. Bonds, Arthur Alexander, Spooner Oldham and Warren Storm, they have a fine old time. I confess I never much cared for Oldham's "Lonely Women Make Good Lovers" when Conway Twitty, Bob Luman and others recorded it in the 1970s. Maybe the Revelers make it seem better than it is, but I enjoy it here.