Puresteel Monolith

Whenever you use Mana produced by fortified land to cast an instant or sorcery spell, you may put that spell card on either the top or bottom of your Library as it resolves. If you do, you cannot cast instant or sorceries with the same name until end of turn.
Fortify {4} ({4}: Attach to target land you control. Fortify only as a sorcery. This card comes into play unattached and stays in play if the land leaves play.)