He sighed, and stumbled over an unseen rock.

He could see waves in the chasm now cresting over unseen rocks, shooting milk-and-amber mist upward.

A driftwood log could pound against him, an unseen rock could hole him, and he would have no warning until it happened.

But though the sound of waves riven upon unseen rocks encompassed them round about, the anticipated wreck did not occur.

Their patio looked down on a wooded stream and Baedecker listened to water running over unseen rocks as he ate his steak and baked potato.

They rocked and teetered along on unseen rocks, passing under the bridge.

She flinched instinctively and fell over an unseen rock, the bag of precious clothes flying from her hand.

What unseen rocks?

She slipped on a mossy rock, unseen in the dark, and sat down, splat, in the middle of the stream.

One foot in front of the other, she kept trekking, stumbling over unseen rocks and tripping in hidden holes.