Not the earliest works of Middle Earth, but where he loses the bits of twee that were in the Book of Lost Tales.
Turin done in alliterative verse, in several variants. The basic bones of the story are down, but many interesting differences between here and the final version.
Luthein and Beren are done in rhyming verse, and come closer to the final version. It makes the Silmarillion version look terse. Some repetitionbetween this and Beren and Luthien.