Glacial Fortress
Land
Glacial Fortress enters the battlefield tapped unless you control a Plains or an Island.
: Add 
or 
.
Ships blown north in their voyage across the Stormwreck Sea become trapped in the unmelting ice.
Illustrated by
Ixalan#255RareEnglishLegality
Rulings
Oct 1, 2009
This checks for lands you control with the land type Plains or Island, not for lands named Plains or Island. The lands it checks for don't have to be basic lands. For example, if you control Watery Grave (a nonbasic land with the land types Island and Swamp), Glacial Fortress will enter untapped.
Oct 1, 2009
As this is entering, it checks for lands that are already on the battlefield. It won't see lands that are entering at the same time (due to Warp World, for example).