primeval

What an animated invasion of this primeval solitude: the prairie nymphs must shrink in amaze! Since the world began, this beautiful meadow was never peopled thus.  --Scenes Beyond the Western Border, May 1852; and Scenes and Adventures in the Army

The word primeval occurs once in Moby-Dick (1851), with reference to the legendary White Steed of the Prairies:

A most imperial and archangelical apparition of that unfallen, western world, which to the eyes of the old trappers and hunters revived the glories of those primeval times when Adam walked majestic as a god, bluff-browed and fearless as this mighty steed.  --Moby Dick, The Whiteness of the Whale

And seven times! in Melville's Pierre (1852), for example:

". . . at fall of eve, Pierre emerged from long wanderings in the primeval woods of Saddle Meadows . . . ."

One instance of primeval in Pierre occurs in connection with deployment of armed troops by a powerful landlord:

" . . . and regular armies, with staffs of officers, crossing rivers with artillery, and marching through primeval woods, and threading vast rocky defiles, have been sent out to distrain upon three thousand farmer-tenants of one landlord, at a blow." 
--Pierre, Book 1

Melville's picture of marching troops entering the forest is similar to the example above from Scenes Beyond the Western Border, where emigrant wagons and dragoons on the march disturb the "primeval" natural setting of a western prairie.