The afternoon came, and the sun, going west towards the mountains, sent out long yellow beams between the cracks and fissures of the clouds.
They had not gone very far when they came upon a great fissure that yawned suddenly black before their feet.
And the air is wholesome there because of the outlets through fissures in the rock far above.
It looked like a great rampart or sea-wall whose foundations had shifted, so that its courses were all twisted and disordered, leaving great fissures and long slanting edges that were in places almost as wide as stairs.
With cautious skill, tap by tap — a small chip of rock and no more, perhaps, in a whole anxious day — so we could work, and as the years went by, we should open up new ways, and display far chambers that are still dark, glimpsed only as a void beyond fissures in the rock.
Dimly the hobbits could discern tall piers and jagged pinnacles of stone on either side, between which were great crevices and fissures blacker than the night, where forgotten winters had gnawed and carved the sunless stone.
There are no more uses of "fissure" in the book.
Show samples from other sources
The earthquake opened a small fissure across the road.
The crisis is creating a fissure in the coalition government.