The tide ebbs. The sun starts to evaporate the moisture from the top surface of a big rock, part of a jetty that thrusts out from the beach. I see a number of dark periwinkles around and under an algae-sheathed, water-soaked branch that lies there, a source of food for these browsers and vegetarians. They are a common marine snail, used for human food in many parts of the world, and usually so numerous and well known as to be taken for granted. As the water recedes and sinks below the surface of the jetty, the sun beats down, drying the rock. Some of the animals stay under the shade and moisture of the stick, but more begin to move slowly away from it. When these travelers finally reach the edge of the rock, they start down its shaded face. Their dark, whorled shells, though an intrinsic part of them, are hoisted, moved around, almost in a full circle, seeming to slip loosely over their bodies as they move down. Their black tentacles, like antennae on insects, wave slightly on their snouts, and their slimy foot works slowly down. Their motion is a curious combination of probing, oozing, gliding, and at the same time, holding on, assuring the grip, with a kind of portentous caution. Since I can easily tip one off with my finger, I also feel a tenuousness about them, in their relation to this realm of tidal power with its constant displacements--but adaptability is probably a better way to think of it. They have lasted, in their loose wandering, through a period of time which we can only estimate. They have a special authority. As I watch them it seems to me that no other action is of any more pressing importance during this moment in the scheme of things. These personifications of motion, these strangers, have untouched lands of their own. That silent sea at my side is colossal, inscrutable, and holds out no solace or advice. We only have our toes in, on a tiny section of its summer shore. Most of us barely touch its surface. Even so, it offers as much to a traveling human as to a snail. It is still an old space unexplored, and if we leave the vacation sands and set out on an afternoon’s sail, we may be following some need of wind and water in us, some unused acquaintance. There is a well-known sand bar to steer by in the hazy distance across Cape Cod Bay. We buck the steely waves upwind, close hauled, half hot in the sun, half cold and shivering when the water thrashes in over the bow of the boat. Ropes creak slightly through the boom and the mast. The wake bubbles. Wood strains through water. The west wind blows stiff over conflicting waves. The time passes with a certain monotony but for the craft of sailors and its requirements. There is nothing called for but to sail, with no other distractions on this immediate flat world of light, no concern ... and yet we sense some ultimate demand that comes from this blue giant, whose depths and tricks are still unfathomed.