This organism lives, and it dies, and quite often when it dies, the broken fragments... drift down... and... can build up... on the floor of the ocean, and over geological time these beautiful little platelets of calcium carbonate become squashed into rocks of calcium... [A]s techtonic plates move around and seas come and go, those rocks can get lifted up and so this... is what the White Cliffs of Dover are made of...

Even castles made of sand,
fall into the sea,
eventually.

...the ocean kept falling into itself, gathering itself up, and falling into itself again.

Castles made of sand, fall in the sea, eventually

And so castles made of sand slips into the sea, eventually.

Wave after wave
Will flow with the tide
And bury the world as it does
Tide after tide
Will flow and recede
Leaving life to go on
As it was... -- Natural Science (1980)

... Time piles rock upon rock. The sea comes and goes with the passing geological ages. Unless other events intervened, my trilobite would have become interred within an ever deeper pile of sediments, to a depth possibly beyond the deepest coal seam, and buried into an obscurity from which it would never emerge. But often in geology that which is buried is destined to rise. Phases of mountain building throw up rocks that were once deep beneath the surface. The British isles have been through no fewer than three such phases since my trilobite scuttled about on the sea floor. The first of these — the — was responsible for disinterring my fossil.

Waves climbed the slope of the beach, fell back, and came again.

Boundaries are a little like the walls of a sandcastle. The second we let one fall over, the rest of them come crashing down.

The tide goes out imperceptibly. The boulders show and seem to rise up and the ocean recedes leaving little pools, leaving wet weed and moss and sponge, iridescence and brown and blue and China red. On the bottoms lie the incredible refuse of the sea, shells broken and chipped and bits of skeleton, claws, the whole sea bottom a fantastic cemetery on which the living scamper and scramble.

Yes, and how many years can a mountain exist before it is washed to the sea?

For water continually dropping will wear hard rocks hollow.

Like cliffs which had been rent asunder; A dreary sea now flows between, But neither heat, nor frost, nor thunder, Shall wholly do away, I ween, The marks of that which once hath been.

"And again and again fell the word, like the ebb of a dying sea.

"Good-bye.