no means of ascertaining, owing to the perishable nature of the defence, but considering that the ancient Britons were of undoubted Celtic origin, we are perhaps justified in assuming it. On the other hand, a row of thick vertical planks driven deeply into the soil and placed closely together upon the summit of a rampart would prove a very formidable obstacle after surmounting 60 feet of steep escarpment under a hail of missiles. The small mounds so often placed as defences near the entrances of fortified hill-tops were clearly intended for a ring of palisades upon their summits, and isolated bastions similarly placed were doubtless treated in the same manner. [Illustration: FIG. 2. SIMPLE STOCKADE OF STONE AND EARTH, RETAINED BY WOODEN STAKES.] [Illustration: FIG. 3. STONE STOCKADE, WITH INNER CORE OF MASONRY.] [Illustration: FIG. 4. WOODEN PALISADE OF TREE-TRUNKS, STRENGTHENED WITH EARTH.] There are no less than five lines of defence upon the south and south-east of Maiden Castle, and a feature of the work is the large amount of room provided upon the summits of the valla to afford accommodation for great bodies of defenders to stand and use their weapons. _Badbury Rings_, four miles N.W. of Wimborne.--This may be classed among the greater hill fortresses inasmuch as it encloses a space of 18 acres and is furnished with three valla and their accompanying ditches. The scarps are in places very steep and 40 feet above the fosses. The eastern entrance is reminiscent of Maiden Castle, a bastion-like obstruction being thrown forward to obstruct ingress, while the great area of standing-room provided for the defenders may be looked upon as characteristic of west country forts as it is repeated in a number of others--Cadbury Castle, near Tiverton, and Shoulsbury on Exmoor, for examples. In the outer area a mound occurs, and ponds also have been formed within the fort. Investigations have brought Celtic antiquities to light and also proved its occupation by the Romans. It affords a magnificent prospect from the summit. In historic times it has been utilised, as in A.D. 901 Æthelwald the Ætheling mustered his men there after Alfred's death, upon the occasion of a popular rising. [Illustration: BADBURY RINGS, DORSET.] _Cadbury Castle._--This is a good example of a contour fort crowning an isolated hill 800 feet in height. Upon three sides are formidable natural precipices, and the ramparts enclose an oval inner space, which is approximately level. The valla are continuous except upon the south, where a scarped drop occurs of about 30 feet to the level of a wide berm, on the outside of which a gigantic rampart rises to the height of more than 20 feet above the berm. [Illustration: THE BERM OF CADBURY CASTLE.]