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turn I found a kind of brownlfl, marly pollers' earth, of unequal Uueknefi, bul which did
nol exceed one foot and a half al the different places I examined.
This marly ftratam ferves as it were to fupport anotlier, much thicker, of black vegetable
earth, wliich became thinner as I approached tlie fea.
Thefe obfeiTations, added to thofe made in my ki t excurfion from Bologna to Padua,
where I vifited the delta formed at the mouth of the PÖ (wlich is continually increafrng by
the fediments of this river accumulaüng from the fame eaufe as before Hated), not only
convinced, but ellabhfhcd me in my former opinion, that this part of Italy is a country by
no means ancient: yet, as there are hüls fcattered in different parts of this immenfe plain,
fach as thofe which are in the neighbourhood of Padua, Lodi, and in the vicinity of
Turin, I was led to examine them with the greateft attention i and tiien I clearly obferved,
on a near inveffigation, that their foil is totally foreign from that on which they ftand,
being moft of them formed of huge blocks of granite and rock ftone, heaped one above
another, covered in great meafure by a calcareous matter, filled with marine fofiils, and
others vifibly formed by volcanic produdUons, fuch as the Enganean mountains, defcribed
in my travels through the Rhfctian Alps, publiihed in 17g2.
From the above proofs it is more than probable that the whole of the lower valley of
Lombardy owes entirely its origin to the immenfe quantities of fediment carried down
by the dilFerent branches of thePo, and other large rivers, which throw themfelves into
the fea near its mouth, and which have thus been daily increafing for feveral centuries.
Keferring even to the ancient hiilory of Italy, we there find Uiat tlie city of Kavennes,
eight miles diJlant fi-om the fea, was m the time of Augnftus fituated at the entrance of an
extenfive harbour, ufed by the Adriatic fleets.
This harbour was defended by two fmall towns, fnppofed to have been the Caifarea and
ClalEs of the ancients, but of which there are fcarcely any veftiges remaining, having been
entirely buried by the atterriffemens or accumulations of the PÓ.
There are however fome valuable and curious fragments exhibited, which have been
dug from thence in the fearches which are made firom time to time; and fome ruins of the
Pharos, or light boufe which ferved to direfl the veffels, are fiffl extant. The major part
likewife of the cities callcd Decapóles, which conflitute the Exarchate • of Ravennes, and
which are now fix or eight miles inland, were, according to Strabo, fmall ifiands as diflant
from the coaft as Venice; and the city of Adria, built by the emperor Adrianus (from
* The countiy fubjea to an exarch.
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whence the exteniive fea which laves that part of Italy takes its name), is well known tô
have been contiguous to it, though it is now above fifteen miles diflant.
Thus it is witli many other cities and towns in the vicinity of this river, as Padua,
Spina, Ponte-Iongue, &c. ; the Euganean mountains were, likewife, as Pliny and Strabo
affert, detached iflands, and the Eleélrides of the ancients.
It is therefore perfectly clear, that tlie lower part of this valley owes its origin to the
caufes already fpecified ; and that, notwitliflanding the many ingenious hydraulic works
which have already been ereiled, and will again in all probability be attempted to prevent
its inundations, it is greatly to be feared that they will only fervc as a mere temporary
relief, and that when it will be no longer poffible to raife the dykes which at prefent
eonti-adl this b-emendous river, it will again overflow the whole of that charming countiy,
which has been gradually encroacliing on the fea, and unfortunately inhabited too foon ;
and that this fertile and luxuriant foil will remain deluged till this formidable river has
again, by tlie cflcits of its fediments, raifed the foil to a proportional height with tlie rife
of its waters, and dug a freih bed capable of containing it ; when, it is to be hoped, it will
gradually drain, and reftorc to its former culture, what it has wrefled by force, though not
witliout having previoufly caufed innumerable ravages and devaflations.
This extenfive valley, of which we have now given a flight defcription, as far as
Verua, contrails by degrees fi-om Cremona to this city, being fcrcened by the Bei^amafche
hills on one fide, and the Montferrat mountains on tlie other j but, immediately on quilting
this town, it begins to widen, and forms the very beautiful plain of Piedmont, which
ferves (if we may be allowed tlie exprefiîon) as a central point for the termination of tliree
extenfive valleys, each watered by a confiderable river. That of Ivrea is fituated on the
right of the Pô in afcending tliis river, and nearly in a northern direction. It leads to the
valley of Aoufle, and tlie famous Mont St. Bernard, which is acknowledged to be one of
the three grand paflages over the Alps to Italy. This valley, which though of vafl length,
becomes gradually narrower as it approaches tlie Alps, has been fo ably defcribed by
Monf, de SaidTure, in liis " Voyage des Alpes," that it will be totally unneceflary to enter
into any particulars concerning it. The Dora Baltea, an extenfive river rifing from
amongfl the glaciers which hang on the fide of this tremendous pafs, waters it in its whole
length, and falls into the Pô near Verua. The direftion of the fécond valley is nearly
from eafl to wefl, and watered by the Dora, which has its fource at the foot of Mont
Genôvre, and throws itfclf into the fame river in the neighbourhood of Turin. The road
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