The speaker comes across a fallen oak whose roots have torn up a chunk of dark red bedrock. It's an ordinary sight, and the speaker says as much: "nothing unusual." But the poem lingers on the details: the three gripping roots, the cracked black bark, the stone rinsed clean by many storms.
Then comes the turn. The speaker imagines the raised rock as a gesture, almost a thrown-back answer to whatever forces brought the tree down. The final line, "Here, take your damn rock back," is blunt and funny, and it gives the roots a stubborn, defiant voice.
The mood mixes quiet observation with dry humor and a little awe. The speaker doesn't mourn the tree so much as admire its last act. The title, "Return," fits both the rock being given back and the tree itself returning to the earth. The casual language keeps the moment grounded, even as the image reaches toward the sky.