Most inhabitants of Zendikar have given up on the idea of an accurate map.

Spreading Seas

Enchant land
When Spreading Seas enters, draw a card.
Enchanted land is an Island.

The List

"Hasty efforts to defend Castle Vantress left it more moat than castle."
—*Last Stand of the Realm*

Wilds of Eldraine: Enchanting Tales

Enchant land
When Spreading Seas enters the battlefield, draw a card.
Enchanted land is an Island.

Zendikar

The enchanted land loses its existing land types and any abilities printed on it. It now has the land type Island and has the ability to tap to produce {U}. Spreading Seas doesn't change the enchanted land's name or whether it's legendary, basic, or snow.