Ere long they were hemmed in in the narrows of the gorge, and all were slain or driven shrieking into the chasm of the Deep to fall before the guardians of the hidden caves.
The great arch still stood, but it opened now upon a roofless chasm: the tunnel was laid bare, and through the cliff-like walls on either side great rents and breaches had been torn; their towers were beaten into dust.
A cliff was on their left and a chasm on their right.
At one point it crawled sideways right to the edge of the dark chasm, and Frodo glancing down saw below him as a vast deep pit the great ravine at the head of the Morgul Valley.
Ahead of them there was a bay in the valley-side, and round the head of this the path went on, no more than a wide ledge with a chasm on the right; across the sheer southward face of the mountain it crawled upwards, until it disappeared into the blackness above.
There are no more uses of "chasm" in the book.
Show samples from other sources
You can’t leap a twenty-foot chasm with two 10-foot jumps.