”
From Evereven's lofty hills
where softly silver fountains fall
his wings him bore, a wandering light,
beyond the mighty Mountain Wall.
The Mountain Wall was a term that appears just once, in Bilbo Baggins's poem Eärendillinwë quoted above. The meaning is not completely certain, but it seems to describe the Pelóri, the Mountains of Defence that ranged along the eastern borders of Valinor.