In some of the entrances the side lintels of slate, granite, and unworked soapstone beams have been found built into the portcullis grooves. In _The Ancient Ruins of Rhodesia_ it was noticed that at several of the ruins therein mentioned stone side lintels were found _in situ_. The stone lintel posts _in situ_ at Zimbabwe had not then been discovered. The tallest of such stone lintels at Zimbabwe is 8 ft. above the ground. The buttresses appear to have been built after the stone posts had been erected, for the walls at the sides of the lintel follow the irregularities of the side faces of the beams. The great destruction which has occurred to these structures might possibly be accounted for by (1) the weight of the stone lintel on getting off the perpendicular, which would lever down the buttress into which it was built; (2) the foundations of buttresses are not so deep as those of the main wall up against which they were built; (3) when some later people, possibly natives, deliberately built up and blocked the entrances they might have used the blocks of these buttresses for their building material; (4) the passage-way between each pair of buttresses being so very narrow, damage could easily have been wrought by ordinary traffic; and (5) the main walls are much higher than the summits of the buttresses, and the walls on either side of the entrances being always more dilapidated on the summits, the falling of huge masses of masonry on to the buttresses immediately below might have effected their destruction. CHAPTER VIII NOTES ON ANCIENT ARCHITECTURE AT GREAT ZIMBABWE (_Continued_) Drains—Battering of Walls—Monoliths—Soapstone Monoliths and Beams—Granite and Slate Beams—Cement dadoes—Built-up Crevices—Holes in Walls other than Drains—Blind Steps and Platforms—Ancient Walls at a Distance from Main Walls—Cement—Caves and Rock Holes. DRAINS IN ELLIPTICAL TEMPLE _Drains through main walls_:— 1. At (352 ft.);[43] from Parallel Passage to exterior of temple; has a decided fall outwards; curves round at half through towards south; covered with large slabs; inner hole 1 in. below granite cement floor of passage, which slopes downwards from either side towards hole; interior opening 14 in. high, 9 in. wide; exterior opening, 12 in. high, 6 in. wide. Between Nos. 1 and 2 drains the cement floor rises a few inches to a raised step-barrier 4 in. high, 3 ft. 10 in. broad, from which the flooring slopes down to No. 2 drain, thus forming catchment areas for each drain to clear off rain-water, so that each drain only had such an area to clear which its capacity would allow.