ment clearly observed in the ruin R.R. v, which shows a closely similar ground-plan, it was possible to trace in the SE. corner indications of stairs leading to the upper story. The interior walls vary in thickness from 3 to 4 feet, while the enclosing walls have one of fully 7 feet. The vaulted chambers of the ground floor had each a narrow loophole to the north. Elsewhere, except for the gate, the enclosing walls were solid, a clear sign of the defensive character of the structure. The upper story rooms appear to have been provided with windows, as suggested by Fig. 481, and probably served as quarters, while those below are more likely to have been used for stores, &c.
Such remains as there were of vaulting in the halls and smaller rooms of the ground floor showed voussoirs of the same type as observed at Ghàgha-shahr, with curved bricks of great size set on their long edge. One measured 28" x 7" x 2". The sun-dried bricks used throughout the structure were large, measuring on the average 24" x 13" x 4". In the enclosing walls, up to a height of about 13 feet from the ground, they were laid in a fashion different from that adopted in any of the ruins previously described ; the bricks were set on edge, with the narrower edge facing outwards. It was of interest to note that here, and also at other posts along the line, the large well-made bricks contained plenty of straw, apparently of wheat. This showed that cultivated ground was probably not very far away, wherever the bricks may actually have been made. The system of vaulting and the size of the bricks clearly indicated that the structure was of considerable antiquity, and the plan, together with the great solidity of the walls, left no doubt as to its defensive purpose. The same explains also the presence of a small outer walled enclosure traceable on the south where the gate lay. As seen in Fig. 480, it had decayed too badly for exact measurement. As already noted, the ruin rises on a low swelling of the ground. The protection afforded by the gravel which covers the surface makes it easy to understand why, in spite of the great age of the ruin, wind-erosion has undercut the ground at its foot nowhere by more than 2 or 3 feet.
The ruin R.R. v (Fig. 479) is situated about 3 miles N. of the Burj-i-chàkar and by the side of the same late canal that passes the latter post and runs on towards Hauzdàr and Machi. The ruin shows a very close resemblance to R.R. iv in all constructive features. For this reason its description may be given here, even though it does not occupy a place in the defensive line proper but lies about a mile and a half behind its nearest post, R.R. xvii. As construction and position show, it evidently formed part of the same system and may well have been intended to provide additional protection for a main route where it passed through the line. As seen from the sketch-plan in Pl. 59, the structural arrangements are practically the same as in R.R. Iv, though the dimensions are somewhat smaller. The building measures 48 feet square outside, and is strengthened at its four corners by round towers now much decayed. The enclosing walls are about 4 feet thick. Here, too, there was an upper story and probably a main gate leading through the south face. But in addition a kind of postern opened into the room at the SE. corner, where the remains of a winding staircase leading to the upper story were still clearly traceable. Of this story very little remained, and the rooms below were all deeply buried in debris, except in the corner named. The bricks, very hard and showing little or no straw, are about 25" x 13" x 4" in size, closely approximating to those observed at Akhur-i-Rustam.1 Fragments of prehistoric pottery were found embedded in the bricks, which suggests that the latter were made at or near the low debris-strewn terrace occupied by the ruin. Up to a height of about 7 feet they are set on edge, just as at R.R. iv, and above that in horizontal courses. The ruin still stands to a height of about 21 feet and shows but little effect of wind-erosion at its foot.
From R.R. v we may now return to the line along which the succession of ruined watch-posts was traced. Taking first that portion of the line which stretches NW. towards the edge of
I See above, ii. p. 945.