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expert medical testimony at a murder trial, of an island continent in the ocean off the entrance to the Mediterranean which was the cradle of civilization. Its people were the conquerors of Europe and Egypt, the colonizers of the Americas, the progenitors of the Mound-builders and the Aztecs. This island, which Plato called Atlantis, with all its inhabitants was swallowed by the sea at a single gulp in one dread day and night.
Then there are the British Isles which are proved by circumstantial evidence to have been, once upon a time, a .part of the continent of Europe. The waves of the Atlantic, pounding ceaselessly awaj, at last gouged a channel through some low-lying lands between Dover and Calais and isolated the islands as a pack of wolves by patient maneuvering might cut out a calf from the herd. And there is Australasia, which is but the meager remnants of a once vast continent which was swallowed by the insatiable waters.
But leaving out of consideration circumstantial evidence, dug up by those who have nothing better to do than to go nosing about trying to pry into Nature's secrets, of transformations in prehistoric times, there still remain changes in modern coastlines great enough to be of more than passing interest. Some of the most striking of these changes are along our own water front.
Inaccuracy and exaggeration by engineers—the fellows who drive tunnels from opposite sides of rivers and mountains and make the ends meet in the black bowels of the earth something less than the fraction of a hair's breadth out of alignment—would be unthinkable, wouldn't they? Well, the engineers of the United States Coast Survey who mapped the coast of Long Beach for twelve miles south of Barnegat Inlet in 1839 found upon going over the ground in 1871 that the sea in thirty-two years had advanced inland an average of 545 feet for the entire distance, and in some places as much as 930 feet. Also they found that beginning at the mouth of Dennis Creek in Cape May County the sea had swallowed 2,310 feet of that stream and 1,880 feet of East and West creeks. When the sea can exhibit an official record of progress at the rate of twenty-three feet a year it almost be
comes eligible to compete with some urban rapid transit systems.
All this happened a generation ago? Yes, but just wait a minute. Dr. George II. Cook, formerly State Geologist of New Jersey, estimated that the coast of the state was subsiding at the rate of two feet a century, or a quarter of an inch a year. The mean seaward slope of the coastal plain being six feet to the mile, this would give a third of a mile per century as the rate of the sea's encroachment upon the land. Dr. Cook being a-mere geologist, engineers could not accept his unsupported statement about the rate of subsidence. So the United States coast survey established bench marks and put up self-registering tide gauges to test the matter. This was a work of years, of course.
Now here is where we get up to date. When the Government employes wearied of the tide gauges the New York City topographical engineers took up the observations. Recently the story the tide gauges told was compared and verified and corrected and tested and analyzed for the whole series of years. When the final result was before them the city engineers had to admit that Dr. Cook had only erred .55 of a foot per century so far as the subsidence of the coasts of New York Harbor were concerned, which wasn't at all bad for a geologist. In other words, they found that while the tide gauges varied somewhat at different points, the apparent average increase at half tide level was 1.45 feet per century. Mind you, they said apparent. An engineer wouldn't admit that coal was black until he had brought his theodolite to bear upon it and had worked out the result with a table of logarithms. And anyway, they said, this did not mean that the sea was really rising; it must be the land sinking if anything was happening. In other words, the patient's leg is fractured, not broken. With this as a basis any one who is good at figures can compute the exact time when the Flatiron Building will be submerged.
It is not necessary to be an engineer or even a geologist to be able to perceive that the sea is advancing upon the eastern and southern coasts of the United States. Submerged stumps, some of them of trees cut down by man, and from a third of a mile to five miles wide which were the low-lying lands which first succumbed to the onslaught of the sea. West of Mobile Bay the keys have gotten out from ten to fifteen miles from the mainland where, being now quite beyond their depth, they are all drowned except a few of the largest which are now dignified by the name of islands.
A tragic incident in this slow drowning of a continent occurred on the night of August 10, 1856, when a sudden storm burst upon the Gulf, lashing its waters to such a fury that L'Isle Derniere, one of the prettiest of these islands, which had been occupied as a summer resort by the richest and oldest Creole families of New Orleans, was overwhelmed with all its inhabitants. Next day nothing but a mud bank, which has been covered at high tide ever since, remained to mark the spot where beautiful L'Isle Derniere had been.
West of the mouth of the Mississippi the Gulf has encroached upon the land from fifty to one hundred miles. Here there are neither keys nor their big brothers, the islands.
One interesting evidence of the steady advance of the sea upon the southern coast was found by the engineers build
Along Thi Yorkshire Coast. England.
ing the jetties at the mouth of the Mississippi. On Belize Bayou, a former outlet of the river, was an old Spanish fort built two hundred years before. When the engineers found it the water was ten feet deep over the door-sill of the magazine. Even if the water had been level with the sill when it was laid, which isn't likely, the rate of subsidence must have been five feet a century. The magazine was level and there were no cracks in the walls, showing that it was settling evenly beneath the waters. It continued to sink while it was under observation during the building of the jetties. But the most singular feature of the land around the mouth of the Mississippi is not that it is sinking but that it also stretches like wet rawhide. It is so elastic and untrustworthy that the jetty engineers could not maintain reliable bench marks, level heights and tide gauges for reference purposes. A carefully measured base line 700 feet long was found to have stretched twelve feet in five years.
This subsidence of the coast, according to the geologists, is caused by the great weight of the detritus deposited upon the edge of the ocean floor by the great rivers. The Mississippi and its
tributaries which are so thick with mud that their waters look as if they needed casters to enable them to run down hill, dump 400,000,000 tons of sediment on the edge of the Gulf every year, which seems quite enough to tip up several states. Yet all the rivers of the world, and that includes the Ganges, which in the average rainy season of 122 days carries six thousand million cubic feet of earthy matter, a bulk equal to "forty of the pyramids of Egypt, do not transport enough sediment to fill up the sea to anyappreciable extent. If an Englishman named Taylor made no mistake in his calculations all the detritus carried by all the rivers of the world in ten thousand vears would only make a layer three inches thick if it were spread evenly all over the bottom of the sea.
The rivers which empty into the Atlantic are not so turbid as the .Mississippi, yet they deposit an ever increasing load of detritus on the ocean floor near their mouths. They do not choke up their entrances because the bottom of the sea sinks as rapidly as the mud accumulates.
On the other side of the Atlantic the coast line is retreating before the ceaseless onslaughts of the waves even more rapidly than here. Forty years ago the area of Great Britain was 56,964,260 acres; today the figures are 56,748,927 acres. The difference, 215,333 acres, represents the amount that has been swallowed by the sea. England alone has surrendered 524 square miles of her territory to the waves within the last thousand years. More recently the advance
of the waters has been much more rapid, averaging for the last forty years 1,523 acres a year. The ravages of the sea in 1903 were almost-unprecedented.
Many historical towns, such as Ravensburgh, where Henry IV landed in 1339, have been submerged. Off the Yorkshire coast alone there are twelve submerged towns and villages. Between Flamborough Head and Kilnsea 73,780 acres, an area equal to that of London, has been devoured by the waves since the Roman invasion. The erosion here is so continuous that the outline of the coast is never the same on two consecutive days. On the Holderness coast, a stretch of forty miles, 1,904,000 tons of material are washed away annually. Spurn Point is about to be made an island.
There is an anchorage off Selsey. Sussex, still called "The Park" because it was a royal deer park in the reign of Henry VIII. The Goodwin sands, so much dreaded by navigators, was the 4.000-acre estate of Earl Godwin until it was inundated by a great wave in 1099. In June, 1898, the sea advanced inland two hundred yards at Cromer during a single gale. Between Cromer and Happisburg, a stretch of sixteen miles, the annual loss is twelve acres. All along the coast the same destructive process is going on continuously. The Shetland Islands, off the coast of Scotland, are composed of very hard rocks; yet so violent is the action of the waves and currents that what were once islands are mere clusters of rocks.