Orphan's Cradle to Oerba, and Back Again
The graphic is a bit mysterious. To clarify, Atomos is a huge, rolling metal sphere with red hot teeth like a buzz saw. Left to itself, it rampages around cutting out new tunnels. If you find it docked, you can board him and ride to Sulyya Springs — or back again to the middle of the map.
You should already know how to go from Vallis Medea to Orphan's Cradle, and vice versa.