208 
altered rocks is a good representa- 
tion of the trias, and the lower lias 
is seen in those wonderful beds of 
statuary and other marble that are 
so well known and highly esteemed. 
Above these, are jurassic rocks, and 
above these again neacomian sand- 
stones, while the chalk is seen in 
the <Alberese, a peculiar limestone 
sometimes approaching marble in 
colour, but not saccharoidal. Ter- 
tiaries of all ages abound in Tuscany, 
from the lowest nummulitic rocks 
to the most recent gravels. 
Tuscany abounds also in metals. 
With Elba close at hand, it may be 
supposed that there is no lack of 
iron. Copper ore, the purest and 
most valuable known, is found at 
Monte Catini, and in one or two 
other spots. At Monte Catini, the 
results have for the last 20 years 
proved as profitable as the deposit 
is remarkable. The copper ore is 
found in kidney-shaped lumps of 
sulphide of copper, mixed irregularly 
in a paste of soft, moist serpentinous 
material. The pockets containing 
the ore are sometimes large, but in 
the highest degree irregular. The 
-lode is a kind of vein in the altered 
voleanic rock of Tuscany, called 
gabro rosso, a singular mass of an- 
gular and rounded material. Mag- 
nesia has played a very important 
part in all the changes and modifi- 
cations that have taken place in it. 
To the presence of magnesia is due, 
among other things, the beautiful 
green marble called serpentine, of 
which there are so many varieties 
in Tuscany; and although the ser- 
pentine rock of the Lizard in Corn- 
wall is of very different appearance 
and hardness, the presence of the 
same mineral causes the peculiari- 
ties of both. 
Lead ore also is found in Tuscany, 
and deposits of some importance 
are worked in various places. The 
lead contains silver. Other metals 
(mercury among the number) are 
not wanting, and there seems a pro- 
spect of the metalliferous deposits 
of Italy soon becoming even more 
worked than in the days of ancient 
Rome, when its produce exceeded 
Notes and Correspondence. 
- stone. 
| Jan. 
that of any country known at that 
time. 
But the working of the marble 
quarries must always be one of the 
most important departments of mi- 
neral industry in northern Italy. 
No one who has not visited Italy 
can imagine the vast development 
of this industry. In Genoa—the 
city of palaces—rightly called the 
superb, marble of the most beau- 
tiful kind and excellent quality, 
of endless variety in colour and 
texture, is almost the only mate- 
rial used for construction. Mar- 
ble staircases, marble balustrades, 
marble pediments, and marble 
floors are seen in every hotel, and 
even in every private house. The 
churches are marble inside and out, 
the public buildings are of the same 
material. In the streets, on the 
piers, and above all, in the Campo 
Santo or Cemetery, wherever we 
may go, the marble is displayed in 
abundance. The same, to some 
extent, is the case at Milan, at Pisa, 
and in most of the other cities 
remarkable for architectural beauty 
or interesting in history. The 
geologist in such a country, and 
under such circumstances, is sure 
to find abundant matter for inquiry. 
The marvellous abundance of marble 
is the result of change or metamor- 
phic action on various beds of lime- 
These changes have origi- 
nated in the volcanic and other 
igneous causes traceable everywhere 
in this part of the world. Active 
volcanoes, in the south extinct, but 
perfect volcanic craters in the centre, 
and occasional earthquakes in the 
north of Italy, are or were the cause 
of the eruptions of sulphurous and 
other gases, and of hot aqueous va- 
pours loaded with mineral matter. 
These are common almost every- 
where, and it is these that have con- 
verted the limestones into marble, 
the clays into shales, and the sands 
into quartzite. Whether we take the 
veined and coloured marbles where 
the impurities or foreign ingredients 
still remain, or the true white and 
statuary marble where the foreign 
substances only occupy small vein- 
