The meeting of composer Arnold Dreyblatt and psych-folk trio Megafaun shouldn’t be seen as unlikely just because it’s cross-generational, or even (arguably) cross-genre. Such categorizations have to be set aside before taking in Appalachian Excitation. The music on their first collaborative recording fits into many styles, but none quite completely. It’s psychedelic in the mind altering (not electric sitar) sense, it hints at Americana but isn’t actually of any nation. The album opens with “Home Hat Placement,” a military march with repeating guitar lines and a snare keeping strict time that resolves in a jagged funk. “Recurrence Plot” slows the gambit to a crawl, becoming a ploddingly persistent procession punctuated with bright chords. “Edge Observation” brings the music down to stasis with sustained tones layered into lush harmonies. If there seems to be a methodology at work, it’s undermined by the closer, “Radiator,” at eleven minutes the longest track of the set, almost proto-punk in its riffing and almost danceable in its rhythms but set apart from any such concerns by clean playing and a tight, modular structure. Categorizing their music is kind of like fitting a hexagonal peg into an octagonal hole: You might be able to force it, but you’ll know it didn’t really fit.