A short time ago I told you something about a strange fight that took
place between a travelling beach and a river. The beach got the best of
it, and the river was obliged to turn aside, and find a way out to sea
in another direction. No doubt if there were Indians living there at the
time, they thought it a great disaster. Perhaps they were in the habit
of sailing down the river to the sea in search of fish and oysters. When
the beach closed up the mouth of the river, they thought it a strange
and terrible event. If it had happened last summer, the people who live
up the river would have called it a great calamity. The river would have
found a new outlet, and perhaps have torn up the land, swept away farms
and houses, and caused great destruction of property. There were no
farms there at the time, for it all happened a long time ago.
There are many places in the world where the sea has cast up sand-bars
and beaches, and has changed the whole face of the country. These
travelling beaches and growing sand-bars sometimes close up the rivers,
and sometimes turn bays into lakes, and these lakes in time turn into
dry land. The great South Bay, on Long Island, is one of these places
where great changes are going on; the meadow back of Chelsea Beach, near
Boston, is another.
When a beach makes trouble for a river, the river behaves very
strangely. At first it is quiet, and does not say much. It rests awhile,
as if to gain strength, and then some day it makes a grand rush, and
tries to break down the barrier the beach has thrown across its mouth.
If it fails, it turns aside and goes out another way; but it soon
settles down into a kind of sullen silence. It seems to be discouraged,
and instead of a swift and pleasant river, it turns into a sluggish
stream that does not seem to care for anything except to creep along in
a lazy fashion.
Now a great and wonderful change begins. Before, it was swift and muddy.
Now, the dull water begins to grow clearer, and the mud and fine sand in
the water sink softly down to the bottom. The water spreads wider and
wider on each side, and instead of a river running into the sea, there
is a broad pool or lagoon behind the beach. Then month by month, year
after year, the river brings down the mud and sand from the country and
drops them far and wide over the broad salt-water lake.
Perhaps the beach in cutting off the river shut in a part of the sea, so
that there are fish and oysters, sea-mosses and crabs, shut in behind
the beach. They do not seem to care. They grow all the better in the
still water, safe from those terrible waves that used to tear them from
the sand in storms. The oysters find the quiet water a good home, and
they grow there by millions on millions. As the old fellows die or are
killed by the star-fish, the young oysters build their homes on top of
the shells of their fathers. Millions of other fish, hermit-crabs,
lobsters, and clams, live and die there, and they too cover the bottom
of the lagoon with their dead shells. Thus it happens that even the
fishes begin to fill up the place by covering the bottom with their
empty houses.
Far up the river are weeds and grasses growing along the edge of the
water. They drop their seeds in the river, and the seeds float down till
they reach the smooth water behind the beach. The sea-birds find the
warm waters of the lagoon a good feeding-place, and they gather there by
hundreds. They too bring seeds from distant places and drop them here.
Perhaps in quiet corners where the water is not quite as salt as in the
sea these seeds find a chance to grow. They spring up on the banks of
mud left here by the tide. The poor things find their new home very
different from the place where they were born, and they have a hard
struggle to live. Still they make a brave fight for existence, and even
if they die, their dead stalks and leaves serve as a bed for new seeds
to live still longer another year.
Then comes another change. The sea plants growing under water find the
still water very different from the open sea where they grew before the
beach cut them off from their home. The river is all the time bringing
down fresh-water, and as the beach cuts off the sea, the water in the
lagoon begins to grow fresh. From year to year the water tastes less
like sea water, and more like river water. The poor plants were meant
for the sea, and the brackish water does not suit them. The beautiful
purple mosses, the long brown weeds, and the bright green sea-lettuce
fade and die. They fall down, and make a black mould on the bottom of
the lake. The poor fish feel it too. The clams and oysters miss the
salt-water. Then the terrible mud smothers and chokes them, and they and
the other fish die, and their empty shells cover the muddy bottom of the
still water.
All this may take years and years, yet the change goes steadily on. The
grasses grow higher, and higher, and tiny spears of marsh grass stand up
out of water where once it was quite deep. The lake is filling up, and
year by year the grass spreads over the water.
[Illustration: OFF BARNEGAT, NEW JERSEY COAST.]
In this picture you see just such a place as this near Barnegat, on the
coast of New Jersey. The grass has already begun to form islands in the
water. The river appears to get discouraged, and wanders about as if it
did not know what to do. The grass spreads wider and wider, and the lake
begins to look like a green and level meadow. Men come in long boots
wading through the shallow water and cut the grass. When it is dried, it
is called salt hay. Cattle like to eat it, for it has a flavor of the
old, old sea that once rolled over the place.
Every year the black wet soil grows firmer. Men dig trenches through it
to let the water drain away. Along the banks of the river they pile the
black peaty sods in long rows. This makes a dike or dam to keep the
river from spreading over the grass in floods. Now the land begins to
dry very fast. Wild cranberries, "cat-o'-nine-tails," and young bushes
spring up. Perhaps a road is laid out over the meadows, and then houses
are built, and boys and girls come to live on the smooth plain that grew
out of the sea.
If you should visit the meadows at Chelsea, in Massachusetts, you would
see just such a lagoon shut in by a travelling beach. It is nearly dry
now, and in summer you will see the farmers cutting the salt grass. The
Great South Bay on Long Island is another place where the change is
going on. If you cross the Hackensack Meadows near Jersey City, you will
see the work nearly finished. This vast level plain was once all water.
The Passaic and the Hackensack rivers still wind through the level
fields, but the work has gone so far that the land is now nearly dry.
How it happened that all this great lake came to be filled up we can not
tell, but we can plainly see that it was once water and is now turning
to dry land.
How do we know all this about these meadows along the coast? Some of the
places look very nearly the same to-day as two hundred years ago. The
Indians never said that the water once flowed here. There is no record
of these things. Indeed! There are plenty of records.
In the first place, you can almost always find the beach at the outside
of the meadows. Nearly all the beaches on Long Island have meadows
behind them. There may not be a river near, but that makes no
difference, for sometimes a beach may grow across a bay between two
capes.
If we dig a hole deep down into such a meadow we may find the whole
story. First we turn up the black sod full of stems and roots of the
grass. Under this the soil is finer, for the roots and leaves have
moulded away. What's that? The spade strikes something hard. It is flat
and rough, and covered with fine black mould. Wash it well, and we find
it is a shell--an oyster shell. Strange that it should be there. Dig
deeper, and we find more, perhaps a great quantity of them, bedded
thickly one over the other. Here's the truth of the matter. This is an
old oyster bed. These oysters did not come there by chance. They must
have lived there, and as they live under salt-water, it is plain that
where we stand was once a part of the sea.
We may dig deeper, and find more records of the old lake. See those
black stones. How smooth and round they are! You remember the smooth
stones we saw rolling in the surf on the beach? We can not help thinking
that these stones were once tumbled about in the surf on some old beach.
This is the way the marsh tells its own story, and repeats the wonderful
tale of its birth from the sea.
[Illustration]