The express trains from Rome to Naples begin their journey with an oblique ascent of the long northern slope by which the ancient Alban volcanic group descends to the Campagna, and thus gain the flat pass near Palestrina, between the old volcanoes and the limestone range on the east. On the way, while crossing the radiating spurs and valleys of the northern slope, fine views are opened on Rome and the Campagna from the embankments, and excellent sections of lava flows and stratified tuffs are shown in the cuttings. In two of the latter the lava beds may be seen in section lying in a broad flat trough of tufaceous shale, and thus indicating that since these lavas were poured down between low radiating ridges on the flanks of the volcano, the ridges have been worn away to produce the existing valleys—an inversion of topography well . . .