On its sixth album, the Swedish band Beardfish continues to purvey its own version of '70s-style progressive rock and heavy metal.

The closest antecedent may be Peter Gabriel-era Genesis, but the musicians (who also sing in nearly unaccented English) also display a familiarity with a wide range of ‘70s performers.

It's really a game of Spot the Influence, as, for example, the 15-minute "And the Stone Said: If I Could Speak" recalls Deep Purple early on with its organ sound, then suggests Pink Floyd as a saxophone comes in.

"Green Waves" brings to mind the traditional heavy metal of Black Sabbath, while the instrumental "Akakabotu" has some of the feel of Frank Zappa's jazz-rock excursions.

And so it goes, with here a passage that sounds like Procol Harum, there a riff echoing Emerson, Lake & Palmer.

The pianist reveals his classical influences with the short interlude "Outside/Inside." The lyrics can be romantically inclined, but also appropriately bombastic, as when the stone, speaking in "And the Stone Said: If I Could Speak," declares, "I was here before you, and I'll still be here when you're gone." Beardfish might be saying the same thing to music fans on behalf of prog rock, and their adherence to the style has the same validity as that of, say, a Dixieland band still playing the music of the '20s in 2011.