ht of two metres. On this was erected a wall of dressed stones,
each successive layer set back, like a step, so that at the top it was
only some two metres in width. It might be thought that this manner of
building offered considerable facilities to an escalading enemy.

On the largest stone of those discovered in 1711 under the choir of
Notre-Dame was deciphered an inscription which recorded the erection of
this altar to Jupiter, "very great, very beneficent," in the reign of
Tiberius Caesar, by the corporation of _nautae_, or mariners, apparently
the most powerful in the city, and the prows of the ships at the foot of
the arches in the ancient palace of Thermes are supposed to have been
connected with the same guild, though this architectural ornament is by
no means uncommon in ancient art. It is from these _Nautae Parisiaci_
that the modern city derives its arms,--a vessel with distended sails.
(If any doubting tourist inquire concerning the maritime commerce of
Paris, he will be proudly referred to the barges which may be seen at
all the quais, and, even more, to the little steamers from London which
contrive to get under the bridges.) In some of the modern records this
ancient corporation is given great importance--with many _sans doutes_
and _il paraits_--in the history of the city, both before and during the
sway of the Romans. Caesar found it "fully organized," though it was
founded on the Roman corporation of the _Nautae Tyberis_, navigators of
the Tiber, composed of senators, magistrates, and knights, which
transported grain and other merchandise from the port of Ostia to the
capital; and it was the original of the later _maison de la marchandise
de l'eau, de l'hotel de Ville et du conseil municipal_ of Paris. The
activity of the Lutetian shippers and navigators covered the territory
bathed by the Seine, the Marne, and the Oise, all of them quite
navigable. The ruins of the Gallo-Roman buildings discovered in the Cite
in 1844, at the opening of the Rue de Constantine, were the remains of a
market or forum for the sale of provisions; and the corporation had,
near the port, an office or bureau for the regulation of this river
commerce. Opposite the port, on the northern side of the Seine, they
controlled also another point of landing, at the Greve, where, later,
was established the _prevote de l'eau_, which developed into the
Parisian municipality. The port on the Cite, on the larger arm of the
Seine, received in