Voice of Thunder

The Etharch lifepath second entry is for a Spell Song called “Voice of Thunder” but I can’t find it in my book (should be on page 152, but it isn’t). What does this one do, and where can I find a write-up? (Or should it just be ignored?)

Voice of Thunder is a skill song. See p. 307.

Sure enough, there it is. Thanks Thor! (page 136 has it marked as a Spell Song, I didn’t think to check the skill section.)