The 4th scroll requires a little leap in logic. The spell on the scroll isn't immediately useful, but it does contain a rune that is. If only there was a way to destroy that rock that is blocking your way...
Even with that hint I’m still stuck. I understand (from this hint) that the spells are essentially spelling messages (eg: FIRE DESTROY, TREE DESTROY, ROCK ROTATE). Given that I’ve tried all the variants I can think of for “ROCK DESTROY” and… none of them work?
I figure ROCK is either the symbol that looks like a bat or the symbol with the triangle. Or maybe it’s both symbols together? None of those with with the symbol for “destroy” doesn’t seem to work.