8
GEOGRAPHY
erosion and collapse, and accounts for those strange subterranean rivers, so remarkable a feature in the scenery of Dalmatia.
  The Karst, as already noticed, runs through the first of Dalmatia’s mountain ranges, the bare and stony Velebit, that huge, repellent mountain mass which dominates the Morlaccan channel and overlooks the lonely, land-locked sea of Novigrad, with Castel Venier and Castel S. Marco, reminiscent of Venetian rule, guarding its approach, and with the first of Dalmatia’s four main rivers, the Zrmanja (Termagna), flowing into the sea of Novigrad by Obrovaz. In such a narrow strip of land between high mountains and the sea we should not expect to find rivers of any great length, nor do we; the Kerka, with its eight beautiful cascades we shall visit from Sebenico, comes down from Dinara, the highest point of the Dinaric range which follows the massif of the Velebit. And from the other side of Dinara springs the longest of the purely Dalmatian rivers, the Cetina, which reaches the sea at Almissa. The mountains now draw nearer to the Adriatic and the width of Dalmatia is reduced to less than fifteen miles near Metkovich and Sabbioncello, where the Narenta, which is not a purely Dalmatian river,