I'm with HLT.
In [i]The One Tree[/i] was wrote:"Therefore it curled its tail about itself and sank into quiescence. And while the Worm rested, the power of the stars wrought within it. From its skin grew excrescences of stone and soil, water and air, and these growths multiplied upon themselves and multiplied until the very Earth beneath our feet took form."
Not only should the Worm have been the core of the Earth, supposedly the rousing itself would be the Earth's demise.
In [i]The One Tree[/i] was wrote:"And the time must come when it is roused, or rouses itself. Then it will slough off this skin of rock and water to pursue its hunger across the cosmos until eon's end and slumber. For that reason, it is named the Worm of the World's End."
As I said, the Last Chronicles was was a bit of a retcon in the Worm area. --- Not that I mind: the cosmos serves the story, the story doesn't serve the cosmos. And we all felt like the Worm itself was a bit of a retcon when we read
The One Tree the first time, didn't we?
Clearly, Donaldson needed a lengthy post-Worm-arousal period to fulfill the sense of doom he required for his story. And so some tweaking.
Certainly the Worm represents Creation, as well as Destruction. But this "representation" was in large part permissible because it was a myth. The actuality of the Worm does more to suggest that there is no Creator than it does to affirm his existence.
Way back in the day, I had proposed a reconciliation of all the myths, by proposing that the Worm was itself the Arch of Time, or at least some part of the Arch which could be touched and triggered and generally cause an Arch-quake.
The Arch is alive. It can be roused. So we need more than one Myth. If you wish to speak about havens against chaos and barriers between the Earth and the Creator, then we speak of an Arch, with the Earth protected within. But if you want to talk about rousing the foundations of the Earth and triggering it's internal urge for self-destruction, then it is not an Arch, it is a giant Worm, and the Earth trembles at its whim. A different fable to tell the same truth in a different way.
I still kind of semi-believe this, even after the Last Chronicles. I think that the power which Jeremiah could see crossing the Land was an avatar of the Arch rather than an actual Worm.