Heidegger and the earth (die Erde)

Some significant quotes from "The Thing" and "The Origin of the Work of Art," that relate to the concept of "earth" and "world," and essentially show that "earth" in the work of art essay comes to stand in for what Heidegger will later develop into "the fourfold:" I'd advise anyone who is reading the work of art essay to read "the fourfold" where they see "earth," and then look at the parts of the essay on the thing to see how the fourfold, in its being owned over to enowning, or, put differently, in the fourfold's belonging-together in the onefold, is "the world:"

The potter makes the eathern jug out of earth that he has specially chosen and prepared for it. The jug consists of that earth. By virtue of what the jug consists of, it too can stand on the earth, either immediately or through the mediation of table and bench. What exists by such producing is what stands on its own, is self-supporting. When we take the jug as a made vessel, then surely we are apprehending it--so it seems--as a thing and never as a mere object. Or do we even now still take the jug as an object? Indeed.
-"The Thing," in Poetry, Language, Thought, 165

The spring stays on in the wate of the gift. In the spring the rock dwells, and in the rock dwells the dark slumber of the earth, which receives the rain and dew of the sky. In the water of the spring dwells the marriage of sky and earth. It stays in the wine given by the fruit of the vine, the fruit in which the earth's nourishment and the sky's sun are betrothed to one another. In the gift of water, in the gift of wine, sky and earth dwell. But the gift of the outpouring is what makes the jug a jug. In the jugness of the jug, sky and earth dwell.
-"The Thing," 170

Our language denotes what a gathering is by an ancient word. That word is: thing. The jug's presencing is the pure, giving gathering of the onefold fourfold into a single time-space, a single stay.
-"The Thing," 171

Earth is the building bearer, nourishing with its fruits, tending water and rock, plant and animal. When we say earth, we are already thinking of the other three [sky, mortals, divinities] along with it by way of the simple oneness of the four.
-"The Thing," 176

To die means to be capable of death as death. Only man dies. The animal perishes. It has death neither ahead of itself nor behind it. Death is the shrine of Nothing, that is, of that which in every respect is never something that merely exists, but which nevertheless presences, even as the mystery of Being itself. As the shrine of Nothing, death is the shelter of Being. We now call mortals mortals--not because their earthly life comes to an end, but because they are capable of death as death. Mortals are who they are, as mortals, present in the shelter of Being. They are the presencing relation to Being as Being.
-"The Thing," 176

...This mirroring does not portray a likeness. The mirroring, lighting each of the four, enowns their own presencing into simple belonging to one another. Mirroring in this enowning-lighting way, each of the four plays to each others. The enowning mirroring sets each of the four free into its own, but it binds these free ones into the simplicity of their essential[/swaying] being towards one another.
The mirroring that binds into freedom is the play that betroths each of the four to each other through the enfolding clasp of their mutual enowning. None of the four insists on its own separate particularity. Rather, each is owned-over-to its own being within their mutual enowning. This owned-over-to-enowning is the mirror play of the fourfold. Out of the fourfold, the simple onefold of the four is put forth/undergone.
This enowning mirror-play of the simple onefold of the earth and sky, divinities and mortals, we call the world.
-"The Thing," 177 (I've deviated significantly from Hofstader's translation in transcribing this: "lighting" I've used instead of "lightening," "put forth/undergone" I've used instead of "ventured," and I've adopted the more modern translation of ereigenen as "enowning" instead of "appropriation" as well as ubereigenen as "owning-over-to" instead of "expropriating:" this has entailed the rearrangement of a few sentences, but overall I hope the passage reads better in this rendering of it.)

The thing stays--gathers and unites--the fourfold. The thing things world. Each thing stays the fourfold into a happening of the simple onehood of the world... Thinging is the nearing of the world.
-"The Thing," 178 (compare "the thing things world" to Heidegger's amazing sentence from Being and Time: "Dasein is the world existingly." Perhaps Dasein as ek-sistence could be said to be that which ek-sists the world? Expressed differently, is ek-sistence the nearing of the world?)