Part 5

By nightfall, water driven by air filled earth and sky. A little ship’s bell on the porch outside kept tinkling, and the wind rained blows on the house. The walls thudded as if they were being struck by rocks. Rain pelted the windows and the cold knifed in between the door and the sill. The sea was putting on a profound and concentrated roar. I went out and fought the wind as far as the top of the bank above the beach. Beyond and below that it was almost impossible to stand. A mountainous milky surf was seething, overturning, and piling in. Fury was riding high. The wind belted houses, shrubs, and scanty trees. The beach grasses were tossed, bent down, and released. Rain slashed and whipped wildly everywhere and it seemed that all the natural power and danger in the world had been let loose. When day broke majestic breakers were booming and pounding down the beach as the north wind drove long lines of spray across their heads.

This is the kind of storm, not infrequent between September and May, that flings down ladders reaching to the beach, undermines or tears away the asphalt parking lots, throws wharf pilings and great ocean-drifting timbers around as if they were matchsticks, and leaves them strewn on the sands. It also tears away tremendous amounts of material from the cliffs, as well as straightening or leveling out the contours of the beach. The cliffs are eroded by storm action primarily, not by the tides; but after a series of storms uncovers a part of the beach, displacing great volumes of sand, sections of the cliff may come down by gravity slippage, because they are not supported underneath, and high tides may help the process.

The extent of cliff erosion is very variable, and in so far as storms are concerned, depends on their degree of intensity. Offshore bars and shoals protect the beach from the action of the sea to some extent. When they are breached during storms, the result is a greatly increased cutting away of the beach sands and erosion of the cliffs. When bars reform and build up again the beach slowly recovers its former volume, though what the cliffs lose, of course, they cannot regain.

The estimate given for the average rate of cliff erosion along the Outer Cape is from two to four feet a year. I have heard of one family who have had to move their cottage back three times during the past forty years, a period in which the cliff, so it was estimated, may have receded nearly 200 feet in that area; and their house lot was not extensive enough for any more moves. Most residents or returned visitors can remember some change in the topography of the cliffs over the years. Not long after the end of World War II, when I came to live on Cape Cod, there were still the remnants of the old twin lighthouses above Nauset Light Beach, in the form of a curved brick base at the top of the cliff. As time went by it was undermined, then started to slide down, reached the base of the cliff to be completely buried by sand, but was uncovered again some years afterward. In South Wellfleet water pipes still project over the cliff, indicating the presence of summer cottages some forty or fifty years ago.

Changes in the beach are more immediate, and not likely to be so irretrievable, but even there it is possible to see its fluctuations over the years. There is a great rock off Nauset Light Beach that used to stand high and clear at low tide some years ago, but it has been undercut and filled around with sand and recently only its top was showing.

This is not a level, stable, protected kind of beach. It is steep, full of long shoulders and curves, and fluctuates in outline not only as a result of storms but with each tide and even with every wave, making new bays, curves, shallow hills, and hollows; but the beach is an interbalanced system. All its materials come from offshore or the erosion of the cliffs. Wave action removes the cliff material, and currents moving parallel to the shore take it both north and south: there being a neutral point around Cahoon’s Hollow, halfway between Highland Light and South Wellfleet, although its location is dependent on the angle at which the waves come in along the shore. Half the cliff material moves north to build up the hood at Provincetown, and half moves south to be deposited along the sandspits from Nauset to Monomoy.

A study made by the Woods Hole Oceanographic Institution, under the direction of John M. Zeigler, points out that the north and south ends of the Cape terminate in fairly deep water, 205 feet off Race Point and about fifty feet off Monomoy, and that: “It seems unlikely that material is moved to the Outer Cape from deep water, either from north and south, or by littoral drifting from any other part of the New England coast. Drifted detritus would be trapped or obstructed many times before it could reach the beaches of the Outer Cape.”

During the course of the same study beach profiles were measured for several years and it was found that the sands were constantly changing in elevation, all the way from several tenths of a foot in one place during a mere ten minutes to a ten-foot loss in another during a period of two days. The average change per tide was about four tenths of a foot and sometimes went up to a foot.

The beach has a kind of rhythmic beat, up and down. If its changes were translated into visual, continuous motion on a screen you might see it dipping, rising, and undulating like the waves at sea. Turbulence and change are not outside a frame of order. Loss is balanced by gain, so that the sand which is taken from one part is added to another, and though the relative volume of the beach is greatly reduced it may be restored in a year or so to more or less its original size.

Zeigler’s report, incidentally, makes the observation that the beaches “become very steep and full in summer and are quite variable in winter, spring and fall,” characteristics governed by the “sea state” during those seasons. Sea state, if I understand the term correctly, refers to the offshore characteristics of the sea surface, the height, length, and steepness of its waves, and their velocity, all governed by the wind in its many different phases. The waves that cut the beach away during fall, winter, and early spring are characterized by their steepness. On the other hand the summer waves that build up the beach, although they may be the same height as cutting waves, are not steep, the long swells that you see offshore in the warm months being typical of this kind.

From Nauset Coast Guard Beach to Highland Light the cliffs range between 60 and 170 feet in height, and they are made of the stones, boulders, sands, gravels, and clays of what geologists up to now have called an “inter-lobate moraine,” meaning the mixed glacial material built up as a ridge along the sides of two moving lobes of ice--in this case two lateral moraines joined as one.

A new study by Dr. John Zeigler, which accompanied his work on beach erosion, puts forth another theory for this area which is that the ridge was already there before the glacier came. It caused the glacier to split into two lobes and the material it left behind was fluvioglacial outwash, there being no real glacial till such as makes up a moraine before Nauset. A carbon dating taken in this lower Cape region puts its age at 20,700 years.

The Upper Cape, from Orleans to the canal, is a true terminal moraine, having material that was pushed ahead of the glacier and left behind when it melted north. It is characterized by uneven hilly country full of rocks and stones merging with a slanting sandy surface on the south which formed the outwash plain.

The cliffs may only be eroded in substantial amounts during storms, but to a slight extent they are always eroding. In some sections, especially during hot and dry weather, there falls a continuous stream of pebbles and granular sand, made a rich reddish-brown by iron compounds, looking in the strong light like a broad rain of precious metals, treasure chests broken open. In other places sheets of fine sand pour down in miniature Niagaras, or flow and fly ahead along the cliffs before the wind, having the look under slanting winter sunlight of light smoke from many fires.

Chunks and fragments of clay are loosened by the weather from their beds in the cliffs and are often washed by heavy rains so that a gray liquid flows and fans out for some feet across the sands. Occasionally boulders will loosen and tumble down. In fact small stones are constantly falling, rolling erratically part way down the beach and leaving their tracks behind them. The cliffs are the prime source of the beach’s materials and a repository of the ages that preceded it. They have a proud and vulnerable role in a context where everything is subject to displacement and removal.

Taking an average of three feet a year, the Outer Beach may have required 1760 years to erode a mile in width, even though that is one of those general figures which may mean nothing so far as detailed geological history is concerned. In any case, not only cottages and lighthouses have gone their way but also such topographical features as marshes and ponds, with all the frogs, fish, and plants that belonged to them. On the cliff tops and very close to the edge, there are many glacial kettle holes, now dried up, but once full of water instead of sand, so numerous in some areas as to make one uninterrupted dip and rise after another. On the Nauset Coast Guard Beach, where the cliffs have ended and are replaced by a long sandspit protecting the Nauset marshes behind it, there is good evidence, jutting out on the beach, of a former kettle hole, showing a fine dark sediment composed of organic material which once lay under beds of peat.

The cliffs’ glacial material, in whatever form they were left on Cape Cod some 20,000 years ago, was part of the land’s erosion, of geology’s rising and falling history, for countless years before that. Since then it has been constantly exposed, loosened, easily eroded and ready for the taking, by winds, tides, and waves, but all of it was changing and movable in terms of the great stretches of earth time. Many of its stones and boulders were being wind and waterworn, cracked by frost and heat, long before they were plucked from hills and ledges, transported and left by the glacier to give the Cape its present form. Now they are being broken out and rolled down to be worn again. Like the tides, they are part of a balance, a flow, and containment, that is prodigious in its reach.

The cliffs erode; the surf churns the sand; currents carry away the sand and other cliff debris; storms cause the sea to break in across sandspits and bars, so that they change constantly in shape and position. There is a magnitude of effect involved at this meeting place of sea and land. It is a magnitude that stretches between a sand grain which may be less than a millimeter in diameter to storms whose force makes man-made explosions of nuclear energy minuscule by comparison.

Sand is perhaps the apex and symbol of the whole process in which the existence of the beach is involved. It is moved and shifted grain by grain in the displacement of its masses, lifted by waves, carried by currents, and set down again. Sand in the evolution of the beach is not a static material but an agent of dynamic energy, following out the motion of water and air, itself their product.

Sand grains, which are of great age, have been worn down from rock and the mineral grains that make it up, to particles, largely of quartz, with some feldspar, that are sufficiently durable not to be reduced to the consistency of mud. The wind which moves the waves and is the ultimate cause of all beach movement, also may have a more important effect than water in abrasing and rounding out a sand grain. The action of grain against grain is more abrasive in the air than in water, which acts as a cushion. In any case a sand grain made of quartz reaches a nearly irreducible size after a long period of time. It might eventually be reduced to powder, but it is now protected by the grains next to it because of its small size and the film of water surrounding it. This water, held there by adsorption, is what makes it possible for tiny animals like nematodes and copepods to exist in such an environment.

Pick up a handful of moist sand and it is heavy and relatively cohesive. Through a hand lens you can see the grains fall off in pearly clumps. On the other hand, dry sand is blown down the beach in its separate grains like rice, and sorted on different levels according to its weight and size. Each sparkling grain is an entity unto itself. It is easily lifted and moved by the energy of waves and currents and at the same time heavy enough in the mass to give beaches their malleable stability.

A sand grain is a product of earth, with beauty, quality, and dynamic character, shining clear in eternal process. Sand has the strength and resilience needed to hold up against the violent tonnage of the waves, and at the same time to share in their employment. It is always being remolded into new shapes by the art of wind and sea, shifting restlessly, moving from age to age. What we call the inanimate not only has its weights and measures but also a wonderful proportion with relation to the forces that send it on. It has a going out that is as rhythmic in its way and as full of viable light as the migration of organic lives.

Dune Country

Sand dunes, as distinct from sandspits, or the banks at the head of the beach, are found in a few restricted areas on the Cape, but their two primary locations are the Provincetown hook and at Sandy Neck in Barnstable, on the Bay side. Inland of the beach, far enough not to be exposed to the constant wash of the tides or to flooding seas during storms, the dunes have forms and motions of their own. They were originally produced by the wind, and it is the wind that reshapes them, blows over their shoulders and down their slopes, making mounds and ripples on their surfaces, and also undoes them and makes new ones again.

The Provincetown dunes, which I had passed by on my June hike down the beach, represent an exposed region of several miles in extent, uninhabited for the most part except for a few gray beach houses perched on the dunes overlooking the sea. They are continually being added to by sand which the dry northwest wind picks up along the shore and blows inland. Because of its dryness, this wind also has the greatest effect in moving the dunes. Damper winds causing moisture on grains of sand, make them more resistant to being moved.

Much of the region is held down by low vegetation. Its sandy reaches are patched everywhere by Hudsonia, or beach heather, pitch pines kept down almost flat on the ground by wind and salt spray, and its slopes and hummocks kept intact by beach grass; but in other areas, and they are extensive, the dunes have broken loose and roam like the waves of the open ocean, with great crests and long, deep troughs. They look as if they should have a slow, massive momentum of their own, but they are moved by the wind, migrating in a west to east direction at the rate of some ten to fifteen feet a year, creating a considerable problem at the point where they skirt the highway across from the town of Provincetown. On the far end of Pilgrim Lake high dunes loom over the highway and are continually drifting down on to it, hardly deterred by snow fences and the planting of beach grass, so that the sand has to be cleared off frequently.

It is a young country, even compared with the rest of the Cape, which, in geologic terms at least, is by no means an ancient land. It is postglacial and is made of material brought along the shore and added to a reef of glacial debris. It begins where the glacial material of the lower Cape ends, easily seen where the cliff at “High Head” breaks off above Pilgrim Lake, and then it stretches and curves out very close to sea level. Samples of material taken in the area showed a carbon dating of 5000 years, comparatively recent times. Also there seems to be good reason for believing that much of the dune country was broken free and set to wandering by the hand of man.

Between the dunes and Provincetown there are a number of ponds, marshy areas, and woodlands, including some good-sized stands of beech and oak. These woods must have been considerably more extensive at one time. In the dunes that now hang over them there are remnants, tree trunks, and stubs protruding through the sand; and there is at least one part of the dunes that seems to show evidence of a wood fire that took up a big area, though when it occurred is not clear to me.