As I lie and look into the pool there are moments of relative quiet, in the intervals when one wave has receded and the next has not yet entered. Then I can hear the small sounds: the sound of water dripping from the mussels on the ceiling or of water dripping from seaweeds that line the walls—small, silver splashes losing themselves in the vastness of the pool and in the confused, murmurous whisperings that emanate from the pool itself—the pool that is never quite still.
Then as my fingers explore among the dark red thongs of the dulse and push away the fronds of the Irish moss that cover the walls beneath me, I begin to find creatures of such extreme delicacy that I wonder how they can exist in this cave when the brute force of storm surf is unleashed within its confined space.
Adhering to the rock walls are thin crusts of one of the bryozoans, a form in which hundreds of minute, flask-shaped cells of a brittle structure, fragile as glass, lie one against another in regular rows to form a continuous crust. The color is a pale apricot; the whole seems an ephemeral creation that would crumble away at a touch, as hoarfrost before the sun.
A tiny spiderlike creature with long and slender legs runs about over the crust. For some reason that may have to do with its food, it is the same apricot color as the bryozoan carpet beneath it; the sea spider, too, seems the embodiment of fragility.
Another bryozoan of coarser, upright growth, Flustrella, sends up little club-shaped projections from a basal mat. Again, the lime-impregnated clubs seem brittle and glassy. Over and among them, innumerable little roundworms crawl with serpentine motion, slender as threads. Baby mussels creep in their tentative exploration of a world so new to them they have not yet found a place to anchor themselves by slender silken lines.
Exploring with my lens, I find many very small snails in the fronds of seaweed. One of them has obviously not been long in the world, for its pure white shell has formed only the first turn of the spiral that will turn many times upon itself in growth from infancy to maturity. Another, no larger, is nevertheless older. Its shining amber shell is coiled like a French horn and, as I watch, the tiny creature within thrusts out a bovine head and seems to be regarding its surroundings with two black eyes, small as the smallest pinpoints.
But seemingly most fragile of all are the little calcareous sponges that here and there exist among the seaweeds. They form masses of minute, upthrust tubes of vase-like form, none more than half an inch high. The wall of each is a mesh of fine threads—a web of starched lace made to fairy scale.
I could have crushed any of these fragile structures between my fingers—yet somehow they find it possible to exist here, amid the surging thunder of the surf that must fill this cave as the sea comes in. Perhaps the seaweeds are the key to the mystery, their resilient fronds a sufficient cushion for all the minute and delicate beings they contain.
But it is the sponges that give to the cave and its pool their special quality—the sense of a continuing flow of time. For each day that I visit the pool on the lowest tides of the summer they seem unchanged—the same in July, the same in August, the same in September. And they are the same this year as last, and presumably as they will be a hundred or a thousand summers hence.
Simple in structure, little different from the first sponges that spread their mats on ancient rocks and drew their food from a primordial sea, the sponges bridge the eons of time. The green sponge that carpets the floor of this cave grew in other pools before this shore was formed; it was old when the first creatures came out of the sea in those ancient eras of the Paleozoic, 300 million years ago; it existed even in the dim past before the first fossil record, for the hard little spicules—all that remains when the living tissue is gone—are found in the first fossil-bearing rocks, those of the Cambrian period.
So, in the hidden chamber of that pool, time echoes down the long ages to a present that is but a moment.
As I watched, a fish swam in, a shadow in the green light, entering the pool by one of the openings low on its seaward wall. Compared with the ancient sponges, the fish was almost a symbol of modernity, its fishlike ancestry traceable only half as far into the past. And I, in whose eyes the images of the two were beheld as though they were contemporaries, was a mere newcomer whose ancestors had inhabited the earth so briefly that my presence was almost anachronistic.
As I lay at the threshold of the cave thinking those thoughts, the surge of waters rose and flooded across the rock on which I rested. The tide was rising.
IV. The Rim of Sand
ON THE SANDS of the sea’s edge, especially where they are broad and bordered by unbroken lines of wind-built dunes, there is a sense of antiquity that is missing from the young rock coast of New England. It is in part a sense of the unhurried deliberation of earth processes that move with infinite leisure, with all eternity at their disposal. For unlike that sudden coming in of the sea to flood the valleys and surge against the mountain crests of the drowned lands of New England, the sea and the land lie here in a relation established gradually, over millions of years.
During those long ages of geologic time, the sea has ebbed and flowed over the great Atlantic coastal plain. It has crept toward the distant Appalachians, paused for a time, then slowly receded, sometimes far into its basin; and on each such advance it has rained down its sediments and left the fossils of its creatures over that vast and level plain. And so the particular place of its stand today is of little moment in the history of the earth or in the nature of the beach—a hundred feet higher, or a hundred feet lower, the seas would still rise and fall unhurried over shining flats of sand, as they do today.
And the materials of the beach are themselves steeped in antiquity. Sand is a substance that is beautiful, mysterious, and infinitely variable; each grain on a beach is the result of processes that go back into the shadowy beginnings of life, or of the earth itself.
The bulk of seashore sand is derived from the weathering and decay of rocks, transported from their place of origin to the sea by the rains and the rivers. In the unhurried processes of erosion, in the freighting seaward, ±n the interruptions and resumptions of that journey, the minerals have suffered various fates—some have been dropped, some have worn out and vanished. In the mountains the slow decay and disintegration of the rocks proceed, and the stream of sediments grows—suddenly and dramatically by rockslides—slowly, inexorably, by the wearing of rock by water. All begin their passage toward the sea. Some disappear through the solvent action of water or by grinding attrition in the rapids of a river’s bed. Some are dropped on the riverbank by flood waters, there to lie for a hundred, a thousand years, to become locked in the sediments of the plain and wait another million years or so, during which, perhaps, the sea comes in and then returns to its basin. Then at last they are released by the persistent work of erosion’s tools-wind, rain, and frost—to resume the journey to the sea. Once brought to salt water, a fresh rearranging, sorting, and transport begin. Light minerals, like flakes of mica, are carried away almost at once; heavy ones like the black sands of ilmenite and rutile are picked up by the violence of storm waves and thrown on the upper beach.
No individual sand grain remains long in any one place. The smaller it is, the more it is subject to long transport—the larger grains by water, the smaller by wind. An average grain of sand is only two and one half times the weight of an equal volume of water, but more than two thousand times as heavy as air, so only the smaller grains are available for transport by wind. But despite the constant working over of the sands by wind and water, a beach shows little visible change from day to day, for as one grain is carried away, another is usually brought to take its place.