NoMap question

Ok, I've made it to the point where I've killed Elder and am sailing around to discover some swamp somewhere. I had an idea to build the cartography table, which I've never done, and it looks like the table itself shows where spawn is, and where my boat is. That may be wishful thinking, I'll find out later. But there's a weird symbol at the top right of the table, sort of like a helmet with overgrown horns, and I can't figure out what that is supposed to be. Anybody got a clue ? Or is it just for looks ?
BTW, for those who want to try NoMap, I've found that I can build signposts at the edges of landmasses to show where it is, so on my home/spawn island I put up a 0 on posts, on the next island over a 1, then 2 for the next, etc. Had a weird bit where I was at 1, trying to sail home with metals, and ran into 2, so turned around and went the other way, only to find 2 again. Turns out my area has a ring of islands, but there's a second one off of 1, which I took for 2 when I went out the eastern side. Bonus: after I figured that out and renamed it 5, I found a draugr willage there. Not quite ready for that one.