The continental shelf is a shallow ocean.
We get shallow oceans covering a smooth planet.
Much of the planet appeared to be covered by a shallow ocean, unbroken by continents.
The suit wasn't built for the depths of even a shallow ocean, and I certainly wasn't.
The surface of Venus, moreover, was known to be almost completely covered with a shallow ocean.
Most birds are found on sand islands in the shallow ocean.
The last edition, just before his untimely death, revealed the significant observation that shallower oceans were geologically younger.
Other units were concealed in the shallow oceans and waited there for the signal to attack.
The ground on which Aullwood lies was once covered by a warm shallow ocean, but remain completely different due to glacial movements.
The area where the Marble Mountains now exist was once part of the flat bottom of an ancient, shallow ocean.