Rituel
Chaque joueur choisit parmi les terrains qu'il contrôle un terrain de chaque type de terrain de base, puis il sacrifie les autres.
You sacrifice all lands other than the chosen ones. Since you can only choose lands with basic land types, any non-basic lands that don’t have a basic land type (even if they have some other land type, as in the case of Cloudpost) are necessarily going to be sacrificed.