Some miles beyond Cagli, the real pass of the Furlo begins. It owes its name to a narrow tunnel bored by Vespasian in the solid rock, where limestone crags descend on the Barano. The Romans called this gallery Petra Pertusa, or Intercisa, or more familiarly Forulus, whence comes the modern name. Indeed, the stations on the old Flaminian Way are still well marked by Latin designations; for Cagli is the ancient Calles, and Fossombrone is Forum Sempronii, and Fano the Fanum Fortunæ. Vespasian commemorated this early achievement in engineering by an inscription carved on the living stone, which still remains; and Claudian, when he sang the journey of his Emperor Honorius from Rimini to Rome, speaks thus of what was even then an object of astonishment to travellers:-- Laetior hinc fano recipit fortuna vetusto, Despiciturque vagus praerupta valle Metaurus, Qua mons arte patens vivo se perforat arcu Admittitque viam sectae per viscera rupis. The Forulus itself may now be matched, on any Alpine pass, by several tunnels of far mightier dimensions; for it is narrow, and does not extend more than 126 feet in length. But it occupies a fine position at the end of a really imposing ravine. The whole Furlo Pass might, without too much exaggeration, be described as a kind of Cheddar on the scale of the Via Mala. The limestone rocks, which rise on either hand above the gorge to an enormous height, are noble in form and solemn, like a succession of gigantic portals, with stupendous flanking obelisks and pyramids. Some of these crag-masses rival the fantastic cliffs of Capri, and all consist of that southern mountain limestone which changes from pale yellow to blue grey and dusky orange. A river roars precipitately through the pass, and the roadsides wave with many sorts of campanulas--a profusion of azure and purple bells upon the hard white stone. Of Roman remains there is still enough (in the way of Roman bridges and bits of broken masonry) to please an antiquary's eye. But the lover of nature will dwell chiefly on the picturesque qualities of this historic gorge, so alien to the general character of Italian scenery, and yet so remote from anything to which Swiss travelling accustoms one.