526 DEPOSITS OF TUSCAN RIVERS. 
charged. The western coast of Tuscany has advanced some 
miles seawards 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, ina still higher propostion, diminished. The 
coast of ancient Etruria was filled with great commercial towns, 
and their rural environs were occupied by a large and pros- 
perous population. But maritime Tuscany has long been one 
of the most unhealthy districts in Christendom; the famous 
Etruscan mart of Populonia has scarcely an inhabitant; the 
coast is almost absolutely depopulated, and the malarious 
fevers have extended their ravages far into the interior. 
These results are certainly not to be ascribed wholly to 
human action. They are, in a large proportion, due to geo- 
logical causes over which man has no control. The soil of 
much of Tuscany becomes pasty, almost fluid even, as soon as 
it is moistened, and when thoroughly saturated with water, it 
flows like ariver. Such a soil as this would not be completely 
protected by woods, and, indeed, it would now be difficult to 
confine it long enough to allow it to cover itself with forest 
vegetation. Nevertheless, it certainly was once chiefly wooded, 
and the rivers which flow through it must then have been much 
less charged with earthy matter than at present, and they must 
have carried into the sea a smaller proportion of their sediment 
when they were free to deposit it on their banks than since 
they have been confined by dikes. 
It is, in general, true, that the intervention of man has 
hitherto seemed to insure the final exhaustion, ruin, and desola- 
tion of every province of nature which he has reduced to his 
dominion. Attila was only giving an energetic and _pictu- 
