rock-bound

Evidence for the greater antiquity of kelp forests, reported this week in the journal Proceedings of the National Academy of Sciences, comes from newly discovered fossils of the kelp's holdfast -- the root-like part of the kelp that anchors it to rocks or rock-bound organisms on the seafloor.

While the people who flocked to the Pacific to enjoy a rare 80F beach day soaked up the sun, so did the mussel beds – where the rock-bound mollusks could have been experiencing temperatures above 100F at low tide, literally roasting in their shells.

Peter had taken a short cut up the steep rock-bound side of the hill.

It might also be the reaction product of water, rock-bound minerals, and ultraviolet radiation.

The eye ranges over a wilderness of fantastic-shaped mountains, some shooting up sharp as arrows, others round and ridgy, separated by sinuous sea-lochs and glittering tarns,—a land of awful ruggedness and desolation,—of rock-bound shores cleft into myriad bays and fiords by the thundering almost ever restless northern sea that beats against them.