Ptolemy also marks, in his map of Britain, some fifty capes, rivers, etc., and the Ravenna list names over forty.
The longitude is reckoned from the "Fortunate Isles," the most western land known to Ptolemy, now the Canary Islands. Ferro, the westernmost of these, is still sometimes found as the Prime Meridian in German maps.
Thus the north supplies not only inscriptions relating to its own legion (the Sixth), but no fewer than 32 of the Second, and 22 of the Twentieth; while at London and Bath indications of all three are found.