I can't figure out how to get the stone (upper left corner) so that I c…

I can't figure out how to get the stone (upper left corner) so that I can activate the teleport in Ruins of Dreamshore. I tried building a tower close by but that didn't expose of enough of it for me to click on it and my scouts can't fly. The walkthough has is magically uncovered so no tips there.. Any suggestions?