Like the title says, I'm trying to complete the Memory of the Tribe.

The only thing I have left is 'The Mask' which is the third or fourth one in 'The Tribe' section.

I've finished the game, and got 100% vegetation on all the levels, so I expect it's a totem I missed somewhere.

Assuming that's the case, does anyone remember which level this is picked up from?

I don't recall which memories are tied to which chapters, but somewhere in the later half of the game (I think you start off at the base of a volcano) there's a memory shrine hidden in the water, tricky to spot. You can't access it unless you dump enough material under it to raise it above the sea level.

Could be that's it.

Google says it's a totem in the Raging Earth level. Look around there.

edit: I think you have to restart the level for it to appear. They seem to cease existing once you finish the level.

@MrKlorox: Thanks! I went back there, and sure enough, it was off the main coastline just far enough that I hadn't seen it for mucking around with the rest of the level.