It was so named because it is covered with a layer of salt deposited long ago by an inland sea .
The Great Salt Plains cover an area of 11,000 square miles ( 28,000 km ) .
Great Salt Plains was so named because Great Salt Plains is covered with a layer of salt deposited long ago by an inland sea .
The Great Salt Plains cover an area of 11,000 square miles ( 28,000 km ) .