I is worth noticing that the rocks are pebble-shaped. This means there were some fluids! Liquid methane maybe? Hydrocarbons or not, Titan is still impressive. Whereas other nearby planets (Mars...) are quite dry & dead (or made of gas, hihi), Titan (of course is not formally a ,,planet''but what a heck) is shaped quite like typical s-f envirovment :l)
Of course, there are other interesting moons in Solar System, take Io (of Jupiter) for instance...
