#AND is hearkens back to the line about grass during the long peace

[softlysilverfountainsfall]

There is an oft-repeated scene in the Silm when one of Our Heroes has died fighting a noble but hopeless battle that they chose, and someone, somehow buries them properly AND it is specifically mentioned in the text that the grave lay undisturbed until some far future date (usually the breaking of Beleriand).

This happens to Finrod, to Fingolfin (though his grave was only undisturbed until Gondolin fell), and Glorfindel. For other dead characters, this precise formula does not occur.

(Beren and Luthien die natural mortal deaths and no one knows where they are buried, Feanor spontaneously combusts and none of his sons' burials are ever mentioned, and Turgon dies & is presumably "buried" in the collapse of his tower. Hurin, Morwen, and Nienor aren't buried [edit: Morwen was buried]; Finduilas and Turin are buried but it is not specifically mentioned that their graves were undisturbed afterwards. Barahir is buried by Beren but it isn't specifically mentioned that his grave was inviolate. Aredhel's grave isn't mentioned, neither is Thingol's, Dior's, or Nimloth's. Aegnor, Angrod, Orodreth, and Gwindor die in battle against the enemy but in a battle that came to them (Bragollach and of Nargothrond respectively) and was one they had to fight, not a hopeless battle that they chose and their graves' aren't mentioned.)

You will notice that I have not mentioned Fingon, who was famously "beat[en] into the dust with their maces...they trod [his banner] into the mire of his blood," or any who died in the Nirnaeth Arnoediad and were dumped in a pile by Morgoth's forces to create the Hill of the Slain/Haudh-en-Ndengin/Hill of Tears/Haudh-en-Nirnaeth.

The Nirnaeth is, of course, the ultimate noble but hopeless battle, and Fingon especially typifies that. (Relatedly, Azahgal's body is successfully borne away by his troops, presumably for a long-lasting burial place.) The Hill of the Slain is meant to be a symbol of Morgoth's power and a place of dreadful carnage and disrespect for those who fell and should break my argument--

But in one sentence Tolkien turns all that around:

"But grass came there and grew again long and green upon that hill, alone in all the desert Morgoth made; and no creature of Morgoth trod thereafter upon the earth beneath which the swords of the Eldar and the Edain crumbled into rust"

--and the symbol of Morgoth's total victory becomes a sacred, untouched grave of heroes.