Closely analogous to these in its main features is the underground structure (Fig. 254) at Buchaam, in Strathdon.[110] It is along narrow gallery entering by a small aperture in the narrow end nearly on a level with the original surface of the ground, gradually widening and increasing in height inwards, and terminating abruptly in a slightly-rounded end. It differs in one respect from the two previously described, inasmuch as though it is curved it has not the double curvature which is the special feature of their form. It curves sharply to the left, but the curvature is not repeated in the opposite direction. It is 58 feet in length following the curve along the middle line of the floor. Its width at the entrance is 3 feet 6 inches, and it gradually widens until it attains a maximum breadth of 9 feet 3 inches. The height increases from about 5 feet near the entrance to about 7 feet at the farther end. The roofing stones were mostly in position and were of great size, some being 7 to 8 feet in length, 3 feet in width, 18 inches in thickness, and weighing more than a ton. The walls rise perpendicularly for 2 or 3 feet and then incline inwards with a curve, so that where the width of the chamber at the floor is 9 feet 3 inches, it is contracted to 7 feet 9 inches at 4 feet above the floor and at the roof to 5 feet. The walls are well built, the lower courses of large cubical stones, undressed, and at the distance of about 12 feet inwards from the entrance there are checks for a door formed of two oblong stones set edgeways in the wall and projecting a few inches from its interior surface. The whole floor of the chamber was paved, and a drain, 10 inches square, well built with a good roof, sides, and bottom, and having a peculiar box-like opening or sink in the inside of the chamber, was found leading from its south-east corner. The chamber when opened was nearly filled with earth and rubbish, and at the bottom there was a layer of fine blue clay 20 inches in depth, which had been carried through the walls by percolation of water from the clay bank outside. In or below this clay which covered the paved floor were found the following relics of human occupation—an iron ring, and an object in iron which looked like the shoe of a wooden spade, some staves of a small wooden cog, a wooden comb, some fragments of pottery of coarse workmanship, a portion of a quern or handmill for grinding grain, fragments of deer’s horns, and bones of the sheep and common domestic fowls. At one corner of the inner end of the chamber the ashes of a fire remained, and immediately above them there was a well-built smoke-hole. ----- Footnote 110: Described by Dr. Arthur Mitchell, _Proc. Soc. Antiq. Scot._, vol. iv. p. 436. ----- [Illustration: Fig. 255.—Ground plan of Earth-house at Culsh, parish of Tarland. (From a plan by Mr. Jervise.) ]