But actually, as I read this part again, like in the other sections, Jackson took the pearls from the book and portrayed them spot-on!
It was after nightfall when they had entered the Mines. They had been going for several hours with only brief halts, when Gandalf came to his first serious check. Before him stood a wide dark arch opening into three passages: all led in the same general direction, eastwards; but the left-hand passage plunged down, while the right-hand climbed up, and the middle way seemed to run on, smooth and level but very narrow.'I have no memory of this place at all! ' said Gandalf, standing uncertainly under the arch. He held up his staff in the hope of finding some marks or inscription that might help his choice; but nothing of the kind was to be seen. `I am too weary to decide,' he said, shaking his head. `And I expect that you are all as weary as I am, or wearier. We had better halt here for what is left of the night. You know what I mean! In here it is ever dark; but outside the late Moon is riding westward and the middle-night has passed.'
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...At length they stirred and looked up, and began to search for anything that would give them tidings of Balin's fate, or show what had become of his folk. There was another smaller door on the other side of the chamber, under the shaft. By both the doors they could now see that many bones were lying, and among them were broken swords and axe-heads, and cloven shields and helms. Some of the swords were crooked: orc-scimitars with blackened blades.
There were many recesses cut in the rock of the walls, and in them were large iron-bound chests of wood. All had been broken and plundered; but beside the shattered lid of one there lay the remains of a book. It had been slashed and stabbed and partly burned, and it was so stained with black and other dark marks like old blood that little of it could be read. Gandalf lifted it carefully, but the leaves crackled and broke as he laid it on the slab. He pored over it for some time without speaking. Frodo and Gimli standing at his side could see, as he gingerly turned the leaves, that they were written by many different hands, in runes, both of Moria and of Dale, and here and there in Elvish script...
`It is grim reading,' he said. 'I fear their end was cruel. Listen! We cannot get out. We cannot get out. They have taken the Bridge and second hall. Frár and Lóni and Náli fell there. Then there are four lines smeared so that I can only read went 5 days ago. The last lines run the pool is up to the wall at Westgate. The Watcher in the Water took Óin. We cannot get out. The end comes, and then drums, drums in the deep. I wonder what that means. The last thing written is in a trailing scrawl of elf-letters: they are coming. There is nothing more.' Gandalf paused and stood in silent thought.