Forum:Strange anomaly under Moria

I noticed an interesting passage in the White Rider chapter in the Two Towers. Gandalf is giving his account of his battle with the Balrog when he says this:

" Ever he clutched me, and ever I hewed him, till at last he fled into dark tunnels. They were not made by Durin's Folk, Gimli son of Gloin. Far, far below the deepest delvings of the Dwarves, the world is gnawed by nameless things. Even Sauron knows them not. They are older than he."

The last sentence of this passage is very strange. As one of the Ainur, Sauron came to being as an offspring of the thought of Eru Illuvatar, before even the creation of Middle Earth. This creates many questions about these "nameless things" that are apparently older than the Ainur. Were these things too created by Eru, or did they come to be in another way? How did they come to live in Middle Earth if they have existed for so much longer? Also, how would Gandalf ever find knowlege of them beyond observing their tunnels? He appears to know a bit of their history which even Sauron, the most powerful the Maia, does not know. I doubt anyone has firm answers to this but it makes for some interesting thought.