Grass[]
Buildings (except Stone Walls, Stone Traps, and Thrones), Units, Stone Circles, Keeps and Castles can be built on this tile. Trees only grow on this type of tile.
Hill[]
Only Tunnels and Units can be built on this tile.
Mountain[]
These are natural barriers--nothing can be built on these, nor can anything move over them. Units with ranged attacks, however, can attack over them.
Shallow Water[]
Only Bridges (built by a Carpenter) and Ships (produced by a Shipyard) can be built here. All naval units can sail in shallow water.
Deep Water[]
Naval Cogs and Bridges are no good here--Naval Carracks, Herring Boats, Explorer Caravels, and Flagships are needed to sail in deep water.
Stone Floor[]
Stone Walls, Stone Traps, and Thrones can be built on this tile, and can be found in Keeps, Castles, and custom realms.