DEPOSITS OF TUSCAN RIVERS. 507 



plouglisliare, and washed down by tlie rain from the hills of 

 Ethiopia which man has stripped of their protecting forests, con- 

 tributes to raise the plains of Egypt, to shoal the maritime chan- 

 nels which lead to the city built by Alexander near the mouth of 

 the Nile, to obstruct the artificial communication between the 

 Mediterranean and the Eed Sea, and to fill up the harbors made 

 famous by Phenician commerce. 



Deposits of the Tuscan Hwers. 



The Arno and all the rivers rising on the western slopes and 

 spurs of the Apennines, carry down immense quantities of mud 

 to tlie Mediterranean. There can be no doubt that the volume 

 of earth so transported is very much greater than it would have 

 been had the soil about the headwaters of those rivers continued 



the continual advance of the land seaward along the Syrian coast, in conse- 

 quence of which Tyre and Sidon no longer lie on the shore, but some distance 

 inland. That the Nile contributes to this deposit may easily be seen, even by 

 the unscientific observer, from the stained and turbid character of the water 

 for many .miles from its mouths. Ships often encounter floating masses of 

 Nile mud, and Dr. Clarke thus describes a case of this sort : 



' ' While we were at table, we heard the sailors who were throwing the lead 

 suddenly cry out : ' Three and a half ! ' The ship slackened her way, and 

 veered about. As she came round, the whole surface of the water was seen 

 to be covered with thick, black mud, which extended so far that it appeared 

 like an island. At the same time, actual land was nowhere to be seen — not 

 even from the mast-head — nor was any notice of such a shoal to be found on 

 any chart on board. The fact is, as we learned afterwards, that a stratum of 

 mud, stretching from the mouths of the Nile for many miles out into the 

 open sea, forms a movable deposit along the Egyptian coast. If this deposit 

 is driven forwards by powerful currents, it sometimes rises to the surface, 

 and disturbs the mariner by the sudden appearance of shoals where the charts 

 lead him to expect a considerable depth of water. But these strata of mud 

 are, in reality, not in the least dangerous. As soon as a ship strikes them 

 they break up at once, and a frigate may hold her course in perfect safety 

 where an inexperienced pilot, misled by his soundings, would every moment 

 expect to be stranded." — BOttger, Das Mittelmeer, pp. 188, 189. 



This phenomenon is not peculiar to the locality in question, and it is fre- 

 quently observed in the Gulf of Bengal, and other great marine estuaries, where 

 immense floating mud-banks are met with. These, like oil on the surface, 

 still the waves, and ships lie-to quietly amongst them. See Nature, Decern* 

 l)er 17, 1874, pp. 135, 136. 



