Dividing the upland into two there marched a double line of unshaped standing stones that dwindled into the dusk and vanished in the trees.
And they fled before the wrath of Isildur, and did not dare to go forth to war on Sauron’s part; and they hid themselves in secret places in the mountains and had no dealings with other men, but slowly dwindled in the barren hills.
The trough between the mountains and the Morgai had steadily dwindled as it climbed upwards, and the inner ridge was now no more than a shelf in the steep faces of the Ephel Duath; but to the east it fell as sheerly as ever down into Gorgoroth.
Soon the dwindling company, following the Isen, turned west and rode through the Gap into the waste lands beyond, and then they turned northwards, and passed over the borders of Dunland.
There are no more uses of "dwindle" in the book.
Show samples from other sources
Her savings dwindled down
I started the diet with good intentions, but my resolution dwindled over time.