240 FROM GALEHDAR TO BUSHIRE [Chap. VIII
lime-plastered, down which the bullocks, drawing water in skins from the well, were driven in the fashion still prevailing in the locality.
The observations made at the Châh-buland strikingly illustrate the rapid progress of erosion on this ground once the rocky surface has been denuded. They also help to explain the origin of similar but smaller towers to be seen in several places within the depression south of Sabzabâd.i0 It deserves to be noted that the mound explored by M. Pézard rises on a broad terrace within two northern branches of the depression. According to the contours of the map on the scale of 4 inches to 1 mile, the foot of the mound lies just 100 feet above sea-level, whereas the bottom of the two ravines flanking the terrace lies more than 20 feet lower. The approximate rate of erosion since chalcolithic times indicated here for the head of the nullah seems to correspond closely enough to the difference between the levels of the terraces previously described as bearing remains of old walls (86 feet by the map) and of the adjacent plateau edge with gang is (100 feet) . But, of course, erosion is likely to make itself felt with greater effect at the lower portions of the nullah than at its head.
In this connexion it may be of some interest to note that according to the meteorological records kept at the Consulate-General, Bushire receives a rainfall which, though erratic, is on the average fairly adequate. During the years 1921 to 1931 it averaged 11.46 inches per annum, with a maximum of no less than 23.60 inches in 1924, and a minimum of only 2.92 inches 111' 1922. It is scarcely necessary to note for the geographical student that the erosive force of rainfall is far greater in an arid or comparatively arid region than in lands with a temperate climate where vegetation protects the soil.
Before concluding these notes on points of some antiquarian interest at Bushire two observations may find record. In several places of the bare ground in the vicinity of the Residency groups of stone heaps attracted my attention by their apparent resemblance to burial cairns such as became familiar to us in Makrân and elsewhere. Some two dozen found scattered over the plateau to the east of the Residency, and at a distance of about 1,000-1,200 yards north of M. Pézard's mound, were all small, measuring up to 4 feet in diameter and not exceeding 2 feet in height. Two of these were opened, but they yielded no finds. Among another group, comprising about a dozen of somewhat larger `cairns' situated about half a mile to the south-east of the Residency on a plateau tongue, one little mound, faced with unhewn stones and measuring about 16 by 14 feet at ground level with a height of 4 feet, was carefully searched. In its centre, filled
to It is possible that by the reference Lieutenant nullah, which he compared with the towers of Pézard makes, loc. cit., p. 36, para. viii, to numerous Portuguese forts at Masqat, such ruined wells are `tours cylindriques ou tronconiques' about the intended.