Rule 301.6

Some artifacts have the subtype “Fortification.” A Fortification can be attached to a land. It can’t legally be attached to an object that isn’t a land. Fortification’s analog to the equip keyword ability is the fortify keyword ability. Rules 301.5a–f apply to Fortifications in relation to lands just as they apply to Equipment in relation to creatures, with one clarification relating to rule 301.5c: a Fortification that’s also a creature (not a land) can’t fortify a land. (See rule 702.67, “Fortify.”)