clear ice

Beneath the clear ice, of perhaps a quarter of an inch in thickness, a mass of fish was swimming with the current.

He had never in his life seen running water before, and must have supposed that he could walk upon it as safely as on clear ice.

For nearly a mile these continue, leaving a gradually narrowing lane of clear ice between them.

Thus a marginal valley is formed, clear ice on one side, or nearly so, buried ice on the other.

The river was frozen over with smooth, clear ice, scarcely thick enough to bear a man.