Great Zimbabwe, Mashonaland, Rhodesia / An account of two years' examination work in 1902-4 on behalf of the government of Rhodesia

by R. N. Hall

These evidences as to the early period during which some of the more distant walls were erected are also found in other large ruins of Southern Rhodesia, but at Zimbabwe, where the Acropolis affords such a commanding view of the lines of walls of the outer ruins and of the directions of recently unburied passages of great length, and of the sweep of the walls connecting main ruins with outlying buildings, the original purpose of many of the walls and minor ruins appears to be very manifest.

In these outer walls the blocks are of far greater size, their shape is frequently irregular, and unhewn stones are employed, but their faces are even on either side and the internal parts are neatly filled in with stones. All these walls have the usual Zimbabwe batter-back, have rounded entrances, and the steps are not built in between the side walls, but are formed by the courses of the foundations. Plumb walls and angular entrances are very rarely met with.

CEMENT

The original builders of the Zimbabwe ruins, as well as those of later ancient periods, can be seen to have shown a peculiar partiality for the employment of cements for all constructive work save that of building the walls, which are all, without exception, of dry masonry. Evidently the ancients, judging by the immense quantity of cement work throughout the ruins, much of which is still in splendid condition, deliberately avoided the use of cement in the construction of the walls. Probably in this respect, and in the employment of blocks of a certain size, they were but following the methods of building to which they were accustomed before their arrival in this country.

(1) The cement work of the oldest periods has been pronounced by practical builders to have been made of crushed fragments of decomposed granite mixed with a large proportion of lime, the latter being found in Suku Glen (see Suku Glen) in extensive areas. This cement is exceedingly hard, and has a glaze on the outer surface which, once broken, has caused the internal body of cement to rapidly decompose into yellow soil. Thus on the faces of steps, dadoes, and all perpendicular work, the cement is more intact, while on flat surfaces where rain-water could not be carried away owing to the stopping up of drains the cement floors are in many instances considerably ruined. Tree roots are rarely found to have penetrated any cement floor which was in a whole condition, and where a root has so penetrated the cement, the root, acting as a conductor of water, has caused all the cement along the line of root to become decomposed. All the roots of trees which have recently been removed from above cement floors are flat, while some of them assume the shape of the structure that was underneath. In one instance the roots of an immense fig tree, which was thought to be over one hundred years old, had wound round and round a circular cement platform which they had failed to penetrate.

This class of cement has been very extensively used by the older occupiers for (a) flooring, (b) dadoes, (c) covering steps and platforms, (d) construction of steps and platforms made entirely of cement, (e) raised rims for dividing floors into separate catchment areas, so confining rain-water over certain areas to particular drains, (f) foundations of walls, (g) for short, low divisional walls made entirely of cement.

(2) There is another class of granite cement which closely resembles the first-mentioned, and this is found on the higher levels. It is also yellow, but in it occur pieces of granite, and it has a decidedly coarser appearance. This is not so lavishly laid, being only one or two inches thick, whereas the former cement is most frequently found to have a thickness of at least 6 in., that is, in those instances where the structures are not entirely composed of this cement. A great quantity of this cement work can be seen on the Acropolis or in the Valley of Ruins.

(3) A further class of cement is of a dull reddish colour, containing more soil than granite. Practically it is clay, but so fine and well polished that it deserves the designation of cement. This work had been burnt white, and its material is very strong and far superior to the best clay used by the oldest native occupiers.

(4) A greyish-coloured cement, in which there are large proportions of lime. This is found in ruins. On the summit of Rusivanga Kopje there are floors and walls made of it. There is difference of opinion between builders and native authorities as to the makers of this cement. It is most certainly superior to any such material made by the natives of to-day. It closely resembles, if it is not identical with, the material used in building the two classes of huts Nos. 1 and 2 (see Native huts found in ruins). The natives state it is not of any known Makalanga make. It is found in large slabs, as if from the side walls of circular huts, fully 14 ft. in diameter, also in bevelled ruins of all sizes. This cement can be seen in some of the ruins, also on Zimbabwe Hill, where the natives state there has been no occupation, excepting, of course, Mogabe’s brief residence, for at least five generations. Judging by the high-class quality of Kafir “finds” here, it is quite possible that this cement is that of the mediæval Makalanga.

(5) The other descriptions of daga (clay) vary in quality from fairly good to most inferior. These are mere veld soil, without being mixed with lime, and are seen in portions of distinctly old Kafir huts resembling the types Nos. 2 and 3. It is also to be found in quantities on the Bentberg and on Rusivanga Kopje. In many trenches can be seen three or four layers of this daga one above another, each layer being about one inch thick, and there are layers of ashes between the floors.