Complex sentence: The Jagged Cliffs area is another region of hundreds of square miles of Athas, north of the Tyr Region, and extends from the Crimson Savanna to the west, The Sea of Silt to the east, and the Burning Plains to the north.
Split into simpler sentences: The Jagged Cliffs region is another region of hundreds of square miles, north of the Tyr region. It extends from the Crimson Savanna in the west to the Sea of Silt in the east, and the Burning Plains to the north.