How is this sentence wrong Fossil fuels are made from the fossils of dinosaurs?

Fossil fuels (coal, oil and natural gas) mostly come from vegetation that was pressurized and heated 300 million years ago. A small part comes from dead animals but not dinosaurs.

But dinosaur fossils are a separate thing altogether.

A correct version of this sentence might read:

Fossil fuels were made, not from fossils, but from ancient organic matter, mostly vegetation, and probably not dinosaurs.