[bombcar]

Tolkien's writing is accurate and descriptive enough to not only produce an atlas [5], and a legendarium of plants [24356] but for said atlas to not only describe the routes, but the types of land/mountains traversed, and how they would have come to be.

[5] https://www.amazon.com/Atlas-Middle-Earth-Revised-Karen-Fons...

[24356] https://tolkiengateway.net/wiki/Flora_of_Middle-Earth

[YeGoblynQueenne]

But, how do we know the atlas etc are accurate? There's no real places or objects to compare them with.

[bombcar]

They're accurate to the text, and "how things are on earth" which is all we can compare them to.

The point being you can have a description of an entirely fantastical area with no inherent contradictions.