Blood Bank (EP). By Bon Iver. Jagjaguwar.

More of the Past (EP). By Vetiver. Gnomonsong.

Back in the day "Extended Play" records -- aka EPs -- were released on both in 12" and 7" vinyl formats to distribute yet-unreleased material, perhaps by an artist whose popularity was on an upswing, or for those with a solid fan base. The concept was later adopted by the CD format. Two exceptional bands have recently released respective EPs, consisting of previously unreleased material.

While the critical iron is hot, Wisconsin-based singer/songwriter Justin Vernon, better known as Bon Iver, has released Blood Bank with four new songs recorded during his much acclaimed debut record, For Emma Forever Ago, which made a number of 2008 Top Album lists.

The title track, "Blood Bank," continues the haunting and melancholic atmosphere that enveloped For Emma, unveiling a story about meeting a woman/lover at a blood bank.

"[These songs] just didn't seem to fit the story and lineage, I guess," Vernon explained in a recent NPR/All Things Considered interview. "So I just sort of surrounded 'Blood Bank' with three other songs that were very different from one other, and they all kind of came together as a palette cleanser for the last record."

"Babys" and "Woods" are the standout cuts. "Babys" starts with a banging, repeating piano riff that lays a fragile foundation for Vernon's multilayered vocals, like a pretty version of an early Velvet Underground song. "Woods" is an a capella number, with Vernon tweaking the multi-tracked vocals with antiquated treatments. It's an interesting and odd technique, one that may be more fully explored on future Bon Iver projects.

Vetiver's five-song EP, More of the Past, presents spillover material from their excellent 2008 release Thing of the Past, a record of obscure covers from the late ’60s/early ’70s period.

Vetiver frontman Andy Cabic has a fine ear for killer harmonies and picking out an obscure gem to cover. What makes these songs work, as on Thing of the Past, are the pristine production (by Cabic and Thom Monahan) and deft execution by the band. Their version of Nils Lofgren's "Just to Have You," a rarity from his days with his 1970s band, Grin, has a loose back-porch quality -- both intimate and freewheeling, allowing the listener to hear the beauty of the song. "Hills of Isle Au Haut," by the reclusive Maine folk songwriter Gordon Bok, is appropriately spare, with the occasional jagged fiddle lines, contributed by underground folk legend, Michael Hurley. The opening cut, "See You Tonight," originally by little-known ’70s Swedish psychedelic band The Wizards, is the knockout song. Filled with swirling electric guitars and cascading vocals, it's a great pop song that defies a time period, yet remains timeless.