against the sea never allow much in terms of residential time, except
to societies that can adapt themselves to living between the wet sand
grains, minute plants, and animals; and beach hoppers that burrow
in on the upper parts of the beach, or other crustaceans that sink
into the sand and out again as the waves go up and back, reacting
simultaneously. It is a terribly exacting place to live in. Life is
short. Disturbance is always to be expected, and the more so in the
course of a storm, which may change the whole physical character of the
beach itself.
While I was walking on the beach I rented a small summer cottage in the
South Wellfleet area during the late autumn and early winter months, so
as to be able to spend nights as well as days by the sea, and I paid it
sporadic visits when I could. I remember one night when the sea showed
me just how candidly elemental and violent it could be. A northeast
storm had been making up all day. Off the Provincetown area, where the
waters are protected by Peaked Hill Bar--extending from Race Point to
High Head, some thousands of feet offshore and parallel to it--the sea
though gray and choppy, was relatively calm, while the wind blew hard.
I could see several fishing boats on the horizon. They were surrounded
by clouds of gulls. The sky was not totally overcast to begin with but
full of handsome blue-gray clouds that sailed across the air like great
round slates. Farther south the gray Atlantic foamed and rocked ahead,
and the green surf came in dashing with spume and spray, pouring an
angry froth on the shore. Finally the sky closed in completely.
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.
V
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.
[Illustration]
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.
Thoreau wrote about the dead stubs of submerged forests projecting
above the surface of the sand in the “desert,” as he called it, and
of numerous little pools in the sand filled with fresh water “... all
that was left, probably of a pond or swamp.” He may have exaggerated
these pools as an indication of former ponds or marshland. They are
located a little above the water level which extends everywhere under
the dunes, and so are likely to be found at the bottom of the dune
troughs, or hollows between the dunes. Some of these pools, or fairly
long and narrow stretches of shallow water, may stay in much the same
place over a long period of time if the levels where they are located
are at least partially held down by vegetation. They are filled up by
rain water during fall and spring and then dry out during the summer
months, but where the dunes migrate before the wind, they also travel
behind one dune and before the next; and they are seldom deep enough to
develop typical swamp vegetation.
Thoreau tramped the area in 1849, and two hundred years earlier the
dune area on the town side of the “Hook” and possibly further must
have been much more circumscribed and held back. The early inhabitants
cut down all the trees they could find, for firewood; “try works” for
melting whale blubber; boats, houses, and salt works (in the days when
salt was produced by boiling sea water instead of the later refinement
of using solar heat to evaporate it).
Blowing sand became a threat to Provincetown and its harbor early in
its history. In his _Cape Cod; its people and their history_, Henry
Kittredge describes the war declared by the people of the town against
almost every stick, living or dead, that surrounded them.
“When the Mayflower band arrived,” he writes, “the sand hills to the
north were for the most part held stationary by trees and shrubs. But
from the earliest times the inhabitants, following the example of
visiting fishermen, fell upon the trees until the sand lay bare, a prey
to the four winds of heaven. The captains of fishing schooners were
allowed to take sand ballast from these hills, and not content with
this, the citizens turned their cattle loose to graze on what clumps of
vegetation still struggled for existence on the denuded hills, with the
result that the grass was demolished as fast as it grew. The sand was
free to blow down upon the unprotected village with every northwester,
threatening even to bury the houses.”
The danger attracted the attention of the Colonial Government as
early as 1714, when an act was passed to preserve the trees. In
1727, Provincetown was incorporated, and a dozen years later another
act forbade the pasturing of cattle on the sand hills. The Court
might as well have forbidden the winds to blow or the sun to shine.
Provincetowners cared nothing for laws, and continued to cut wood and
turn cattle loose for the next hundred years; in short, until the
danger, instead of threatening, actually arrived. The sand buried
a house or two, and was advancing toward the town, salt works, and
harbor at the rate of fifty rods a year along a four-and-a-half-mile
front. In 1825, another commission was sent to study the situation
and suggest remedies. This time they found the citizens so frightened
by the marching sand that they were ready at last to obey the laws.
They planted beach grass on the barren dunes, kept their cattle in the
pound, and stopped cutting down young pine trees. Thus was the sand
anchored and the town saved.
Pilgrim Lake is what is left of East Harbor, an extension of the main
harbor of Provincetown that ended in marshes separated by a narrow
strip of beach on the outer shore. The sea was a constant threat to
this barrier and the people of Provincetown were afraid that it would
eventually break through and start sending tons of sand into their
valuable harbor, eventually making it unusable. A dike, 1400 feet
long and seventy-five feet wide was finally completed in 1869, cutting
across the mouth of East Harbor at the entrance to Provincetown Harbor,
so that both houses and fishing industry were no longer threatened with
burial; but the dunes, though held in some control, have continued to
blow.
There is a small hill called Mt. Gilboa on one side of the highway at
Provincetown, facing another Biblical peak called Mt. Ararat on the
other, and if you climb it you can overlook the harbor and the roofs
of the town, as well as the dunes and sea in the other direction.
(Provincetown, incidentally, consists of a belt of houses narrowly
strung along the inner shore with its streets directly oriented toward
the harbor, appropriate to a people whose trade and thoughts were
toward the sea. This is also true of the houses, which were built
longitudinally, parallel to the streets.) In the fall, clam diggers
bend down over dark flats at low tide between stretching fingers of
water. Dories are stranded in the mud, or move gently on low water.
Beyond them are the curving, stockadelike enclosures of the fish weirs,
and draggers move in to the mouth of the harbor out of the bay. The
sunlight fires the sandy faces of the long, low cliffs that extend down
the inner shore of the Cape.
The town, which is so thick and crowded with cars during the summer
months, a host to the cities, teeming with talk and color, a variety
of human shapes, sizes, and exclamations, so reclaimed that you can
hardly conceive of its austere past, becomes diminished again to a mere
cluster of houses, a tenuous edge on water and sand. On the far-going
Atlantic side, the dunes billow and toss. The Ararats are everywhere,
peaks, crowns, domes held down by yellow beach grass on the mounds and
hillocks from which the slopes dive down.