Large blocks of stone, shaped to fit the upper surface of the rock, were laid upon it, generally endways, that is, with their smallest surface outwards, their length forming the thickness of the wall, which was sometimes as much as fifteen or twenty feet.[648] The massive blocks, once placed, were almost immovable, and it was considered enough to lay them side by side, without clamps or mortar, since their own weight kept them in place.

It was not thought of much consequence whether the joints of the courses coincided or not; though care was taken that, if a coincidence occurred in two courses, it should not be repeated in the third.[649] The elevation of walls does not seem to have often exceeded from thirty to forty feet, though Diodorus makes the walls of Carthage sixty feet high,[650] and Arrian gives to the wall of Tyre which faced the continent the extraordinary height of a hundred and fifty feet.[651] If we may generalise from the most perfect specimens of Phoenician town-walls that are still fairly traceable, as those of Eryx and Lixus,[652] we may lay it down, that such walls were usually flanked, at irregular intervals, by square or rectangular towers, which projected considerably beyond the line of the curtain.

The towers were of a more massive construction than the wall itself, especially in the lower portion, where vast blocks were common.

The wall was also broken at intervals by gates, some of which were posterns, either arched or covered in by flat stones,[653] while others were of larger dimensions, and were protected, on one side or on both, by bastions.

The sites of towns were commonly eminences, and the line of the walls followed the irregularities of the ground, crowning the slopes where they were steepest.