It's a fun if rather bizarre fantasy setting, basically set on a sort of peninsula that juts out into empty space, with a large city near the tip, then a really big old swamp, and then deep forests that make up most of it. In the older parts of the setting, (the "first age of flight"), there are lighter-than-air "flight rocks" (IIRC they get heated to make them light enough to make the ship buoyant) which then have what are basically old fashioned sailing ships built around them, carrying knights or pirates or traders out to the Deepwoods to get various raw materials etc.
This sort of thing (with the flight rock taking up most of the central globe):
So totally different in theme and in how the rocks work to what you're doing, but the importance/centrality of flight rocks was what reminded me