414 
DEPOSITS OF THE TUSCAN EIVEK9. 
Deposits of the Tuscan Rivers, 
The Arno, and all the rivers rising on the western slopes 
and spurs of the Apennines, carry down immense quantities 
of mud to the 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 to be protected from wash by forests; and 
there is as little question that the quantity borne out to sea 
by the rivers of Western Italy is much increased by artifi¬ 
cial embankments, because they are thereby prevented from 
spreading over the surface the sedimentary matter with which 
they are charged. The western coast of Tuscany has advanced 
some miles seaward within a very few centuries. The bed of 
the sea, for a long distance, has been raised, and of course the 
relative elevation of the land above it lessened ; harbors have 
been filled up and destroyed; long lines of coast dunes have 
been formed, and the diminished inclination of the beds of the 
rivers near their outlets has caused their waters to overflow 
their banks and convert them into pestilential marshes. The 
territorial extent of Western Italy has thus been considerably 
increased, but the amount of soil habitable and cultivable by 
man has been, in a still higher proportion, diminished. The 
coast of ancient Etruria was filled with great commercial 
towns, and their rural environs were occupied by a large and 
prosperous population. But maritime Tuscany has long been 
one of the most unhealthy districts in Christendom; the 
famous mart of Populonia has not an inhabitant; the coast is 
fill up the lagoons on the coast, and the remaining ten, even allowing the 
mean depth of the water to be twenty fathoms, which is beyond the truth, 
would have been sufficient to extend the coast line about three miles far¬ 
ther seaward, and thus, including the land gained by the filling up of the 
lagoons, to add more than five hundred square miles to the area of Egypt. 
Nor is this all; for the retardation of the current, by lengthening the 
course and consequently diminishing the inclination of the channel, would 
have increased the deposit of suspended matter, and proportionally aug¬ 
mented the total effect of the embankment. 
