A person sits beneath a cliff, hiding from the heat, and suddenly announces a huge ambition: to find "the bottom of the possible." It's a grand, almost comic statement for someone just sitting in the shade. The poem then undercuts it. A wren, a tiny bird, offers its opinion that the sea is "too tedious," as if even nature finds the big quest boring. Then the speaker admits something quieter and more honest: "I have lost myself / in the sand."
The mood is drowsy, wry, and a little dreamlike. The speaker seems to start with a sense of purpose and end up dissolved into the landscape, with no clear answer. Judging by the images, the search for limits may be less a dramatic journey than a drift. The title, "Littoral," refers to the shore, the in-between zone of land and sea, and that fits a speaker caught between wanting to dive deep and simply lingering at the edge.