The hill itself is nearly conoidal, rather narrower in its N. E. and S. W. diameter, than at right angles thereto: it is extremely steep, and rises from 900 to 1000 feet (by the eye) above the river Agri.
The town covered the summit, and spread some way down the flanks all round, descending most, upon the east side. The ancient Norman Castello Cilliberti, crowned the crest, which was bare limestone rock, and equally bare for 200 or 300 feet downwards. Beds of increasing thickness of alluvium then begin to cover it, and as it slopes down rapidly at an angle of nearly 45° to the Agri, these become 70 to 100 feet thick.
The opposite bank of the river, running N. W. to S. E., which I can see about 400 feet below me, consists of still deeper alluvium, forming part of the Piano Spineto, &c., resting upon horizontal and exposed beds of clays and schaly argillaceous rocks.
To the north and N. W., beyond the hill of Saponara, the Piano of Mattine delle Rose, extends for some five or six miles, all of such formations, and beyond that the mountains rise to Marsico Vetico, and beyond to the crest of Monte Voltorino. It was from this direction that the blow reached Saponara—delivered end on through its vertical beds, from the vast mass of loose material of the piano. Insulated to a depth of 1000 feet, the Agri and Sciavra running round its base from N. W. to south, peaked, narrow, and abrupt, and surrounded by horizontally abutting, dense and inelastic formations, the summit of the hill and the unhappy town upon it, must have shook and swayed like a mast, after the shock of the 16th of December.
The appearance of the ruin of Saponara was appalling.
