The chief point of interest, however, lay in the peculiar structures which surrounded the island. These consisted of a series of rectangles, some 60 in number, formed of horizontal beams 16 feet long and 8 to 12 inches in diameter; they overlapped each other near their extremities, leaving about 18 inches free, and each beam had deep cuts by which it was kept in position, exactly similar to the plan used in the construction of a log house. The rectangular spaces measured four or five square yards, and had 30 or 40 piles placed on both sides of the chamber-walls, apparently for the purpose of strengthening the horizontal beams, as shown in the plan. These chambers appear to have formed a complete girdle to the island, but they were partly destroyed on the south side. The quantity of wood used was enormous, as the piles alone numbered about 1800. On the north side the structures were remarkably well preserved, being protected by a covering of slime and rushes eight to twelve inches thick. At first Major Kasiski believed that the rectangles were cottages, but subsequently, after comparison with similar structures in other lakes in North Germany, he came to the conclusion that they formed merely the submerged foundations over which the cottages had been built. The bridges from the Insel to the Werder, and from the Werder to the shore, were built on two rows of piles, 8 feet apart, and the piles in each row were about 7 feet apart. Major Kasiski inferred from the remains of the unfinished bridge, which showed the use of tenons and mortises, that it was of later date than the others. Among the relics collected on the island or amidst its surrounding structures are two halves of an upper quern, 14½ inches in diameter and 5 inches thick. The under side is concave, and the centre hole, which has a diameter of 1¼ inches, widens upwards like a funnel. Querns have been found in several lake-dwellings in North Germany, as Gägelow, Wismar, and Cottbus, in Neumark.[54] Other relics consist of wooden clubs, two portions of leather, a skate made of the leg-bone of a horse, staghorn hammers, five sharpening-stones, a few spindle-whorls of stone and clay, a bit of coral, seven portions of worked wood--a shovel, rudder, etc. Of metal there are a fragment of bronze and an iron hatchet. The latter implement is small, measuring only 3½ inches long, and 2½ inches wide at its cutting-edge, and has a round hole for the handle. The pottery, of which 45 fragments were collected, was made of fine clay, by means of the potter's-wheel, and from the variety of its ornamentation and characteristic wavy lines, there can be no doubt that it belonged to the type of the Burgwälle--an inference which is greatly strengthened by its resemblance to that found in the Wallberg in the Raddatzsee, a noted Burgwall situated in the close vicinity. Illustrations of a few specimens of this pottery are given on =Fig. 96=, Nos. 6 to 9.