These larger fosses are of rock, and the bridges also; but as he goes further into detail, Dante tells us of various minor fosses and embankments, in which he anxiously points out to us not only the formality, but the neatness and perfectness, of the stonework. For instance, in describing the river Phlegethon, he tells us that it was ‘paved with stone at the bottom, and at the sides, and over the edges of the sides ,’ just as the water is at the baths of Bulicame; and for fear we should think this embankment at all larger than it really was, Dante adds, carefully, that it was made just like the embankments of Ghent or Bruges against the sea, or those in Lombardy which bank the Brenta, only ‘not so high, nor so wide,’ as any of these. And besides the trenches, we have two well-built castles; one like Ecbatana, with seven circuits of wall (and surrounded by a fair stream), wherein the great poets and sages of antiquity live; and another, a great fortified city with walls of iron, red-hot, and a deep fosse round it, and full of ‘grave citizens,’⁠—the city of Dis.