). Ptolemy in his description of the coast of Celtogalatia Aquitania (2.7.1) proceeds from south to north. Next to the outlets of the Garonne
he places Santonum Portus, and next to it Santonum Promontorium (Σαντόνων ἄκρον
The outlet of the river Canentelus is placed north of the promontorium.
The carantonus of Ausonius is certainly the Charente
]; and Ptolemy's Canentelus is a different river, or, if it is the same river, he has placed it wrong.
It is impossible to determine what is the Santonum Portus of Ptolemy. If it is Rochelle,
as some geographers maintain, and if Ptolemy's Canentelus is the Charente,
he has placed their positions in wrong order.
It seems very unlikely that Ptolemy should mention a river between the Garonne
and not mention the Charente.
The only other large river between the Garonne
and the Loire
is the Sévre Niortaise,
which is north of La Rochelle,
and if Ptolemy's Canentelus is the Sèvre,
the Santonum Portus might be La Rochelle.
D'Anville supposes Santonum Portus to be the embouchure of the Seudre,
which opens into the sea opposite the southern extremity of the Isle d'Oléron;
but he does not undertake to fix the position of the Santonum Promontorium.
The latitudes of Ptolemy cannot be trusted, and his geography of Gallia is full of errors.