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Of small Lakes that are turned into dry Land we have several Inftances, especially in Holland.

PROPOSITION VII.

Streights are dried up and turned into Ifthmus's, or Parts of Continents.

THIS is caused by the continual gathering and fubfiding of the Mud and earthy Matter, which in Time choaks up the Streight, and stops the Intercourfe of the Water.

THUS it feems very probable that the Ifthmus between Africa and Afia, which parts the Red-Sea from the Mediterranean, was formerly a Streight and joined them. The Depth of the Sea in feveral Streights is alfo found to grow lefs, and the Water to become fhallower than it used to be, which is a certain Sign that fuch a Streight, fome Time or other, will be left bare, and be turned into dry Land. So that Bay in the Atlantic Sea which the Hollanders call the Zuider Sea, and the Streights of the Texel, will not now admit of loaded Ships of the firft or fecond Rate, as they ufed to do formerly; and as the Water evidently leffens and becomes fhallower every Year, it is likely the Texel, will one Time or other, become dry Ground: and that Streight which they call Ulie will, very likely, have the fame Fate.

PROPOSITION VIII.

Bays may be in time dried up, and turned into firm Ground.

THIS may happen from a two-fold Caufe: 1. If the Streights which join the Bay to the Ocean become an Ifthmus, or be choaked up with Sand

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and Mud (that fuch a thing may happen, we fhewed in the laft Propofition); by this means the Bay is cut off from the Ocean, and becomes a Lake, which is turned into a Fen, or Bog, and then intodry Ground. 2. If the Chanel of the Bay be heightened continually by the Sand and Gravel, brought down by the Rivers into it, it will in Time be higher than the Ocean, and receive no more Sea-Water.

THUS the Mediterranean, Baltic, Red-Sea, Perfian Gulph, &c. which are now Bays, may be changed, one Time or other, into dry Land; as we shall further prove in the next Propofition.

PROPOSITION IX.

The Ocean in fome Places forfakes the Shores, fo that it becomes dry Land where it was formerly Sea.

THIS is caused by these Means: 1. If the force of the Waves dashing against the Shore, be broken by Cliffs, Shoals, or Rocks, scattered here and there, under Water, the earthy Matter contained in the Water, as Slime, Mud, &c. is made to fubfide, and increase the Height of the SandBanks, whereby the Violence of the Ocean is more and more refifted, which makes it yield more Sediment; fo that at length the Sand-Banks, being raised to a great Height and Bulk, entirely exclude the Ocean and becomes dry Land. 2. It contributes much to heightning the Shores if they be fandy and rocky, for then the Sea dafhing against them, and withdrawing, carries little or nothing away from them, but every Time it approaches them it brings Dregs and Sediment, whereby they are increased in 'the Manner aforefaid. 3. If fome neighbouring Shore confift of light, mouldring, porous, Earth, which is eafily VOL. I. washed

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washed away by the Flux of the Sea, it is mixed with the Water, and left upon fome other adjacent Shore that is harder; befides, when the Sea encroaches upon one Shore, it relinquishes another not far off. 4. Large Rivers bring down vaft Quantities of Sand and Gravel to their Mouths, (where they exonerate themselves into the Sea) and leave it there, partly because the Chanel is wider and fhallower, and partly because the Sea refifts their Motion; but this is chiefly obferved in Countries, whofe Rivers annually overflow their Banks. 5. If frequent Winds blow fom the Sea to the Shore-wards, and the Shore itself be rocky or of tough Earth without Sand, it gathers Slime and Mud, and becomes higher. 6. If the Tide flow quick, and without great Force, but ebb flowly, it brings a great deal of Matter to the Shore, but carries none away. 7. If the Shore defcend obliquely into the Sea for a great Way, the Force of the Waves are broke and leffened by Degrees, and the Sea leaves it's Filth and Slime upon it.

THERE are feveral Places of the Earth, which, it is certain were formerly covered by the Ocean. Where Egypt is now, it was formerly Sea, as appears both from the Teftimony of the Antients, and Experience; for the Nile, flowing from the remote Regions of Ethiopia, when it overflows it's Banks, covers all Egypt for a Time, and then fettling by Degrees, it leaves the Dregs, Mud, Dirt, and earthy Matter, which the fwift Course of the River had brought down; by this means Egypt becomes annually higher and higher. But before fuch a Quantity of Matter was brought down to the Nile, the Sea covered the Land of Egypt, tho' it be repulfed and hemmed in now by the Earth's acquired Altitude. Ariftotle, among others, afferts this, and fays: This Place, and the whole Coun

try (meaning Egypt) were formed by the pouring in of the Nile, and feems to gain Firmness every Year. But fince the neighbouring Inhabitants, by Degrees, began to cultivate the Marfhes and Bogs as they dried up, it is impoffible to guefs at the Time of this Mutation. However, it feems that all the Mouths of the Nile have been made by Hand, and not by the River, except that of Canopus. It is further evident, that all old Egypt confifted only of one Town, which they called Thebes. Homer declares this, who flourished (I may fay) not long after thefe Changes; for he men tions that Place as if there were then no fuch City as Memphis, at leaft not fo large. Seneca explains this better thus: Egypt (fays he) arose wholly at first from Mud; and if we may credit Homer, the Ifland of Pharos was fo far diftant from the Continent, as a Ship, with all her Sails fpread, could fail in a Day, but now it is joined to the Continent; for the Nile flowing muddy and troubled, and carrying down much Slime and Dirt, leaves it about it's Mouths, whereby the Continent is annually enlarged, and Egypt is ftretched further and further every Year. Hence comes the Fatnefs and Fertility of the Soil, and also it's Evennefs and Solidity; for the Mud fettles and grows dry and hard, and the Ground becomes firm by what is laid upon it.

THE Ganges and Indus, both famous Rivers in India, do the fame as the Nile, by their Inundations; alfo the Rio de la Plata in Brafil. And it is very probable that China was formed by this means, or at least enlarged; because the impetuous River, called the Hoambo, flowing out of Tartary into China, and frequently overflowing it's Banks, (tho' not annually) hath fo much Sand and Gravel in it, as to make a third Part of it's Waters. THESE

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THESE Examples demonftrate the fourth Caufe, viz. that Rivers make the Sea forfake the Shore; but the Sea itself, in feveral Countries, is the Cause of it's own retiring, by bringing to the Shore, and there leaving Sediment and Matter enough to encrease the Altitude of the Coaft; so that it fuffers not the Sea to overflow it any longer. Thus Holland, Zeeland, and Gelderland, were formed; for the Sea covered thefe Countries formerly, as is known both from the antient Monuments mentioned in History, and the Quality of the Soil itself. In the Mountains of Gelderland, not far from Nimeguen, there are found Sea-Shells, and at a great Depth in Holland are dug up Shrubs and ouzy matter; add to this, that the Sea itself is higher than thefe Countries, and would overflow and cover them, but that it is restrained by Banks and Dams. On the other hand, there are fome that think Holland and Zeeland arofe from the Mud and Sand brought down by the Rhine and the Maes; nor is this unlikely. Pruia alfo and the adjacent Countries daily become larger by the Sea's retiring.

PROPOSITION X.

To explain the Origin or Rife of Sand-Banks.

BY Sand-Banks we understand large Collections or Cliffs of Sand in the Water, standing up above the Chanel of a River, to fuch a Height as to hinder the Paffage of Ships. The Dutch Sailors call them een Droogte, een Banck, een Rifs; the Portuguese, Abrothes, and Baixes. They differ not from Rocks, only that Rocks are hard, folid, and coherent in their parts; whereas Sand-Banks confift of grains of Sand, that ftick more loofely together. thefe two are often confounded. !

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