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Hillfort. The Brown Caterthun is a multi-vallate and probably multi-period hill-fort, unique in that although some smaller and less complex structures in southern Aberdeenshire show comparable features, no close parallel is known. Six lines of defence surround the flat summit of a gently rising hill, the innermost being a ruinous stone wall 3.5 m broad and 0.3 m in maximum height, enclosing an area 79 m by 61 m, with a single entrance in the north. Outside this, at distances ranging from 18 m to 55 m, runs a heavy rampart which may have originated as a wall, and which is now spread to a breadth of about 7.6 m. Several stretches of large boulders occur along its outer face, and it has nine entrances. Two ramparts with a median ditch, 6.0 m wide and 0.5 m deep, closely surround this wall and are probably contemporary with it. They also have nine entrances. Outside these runs a rampart with no apparent ditch, which has a pronounced and unaccountable kink in the east. This has eight entrances, as has the outermost line of defence, a rampart with a narrow 0.5m deep, external quarry ditch, which more or less parallels the line of the former and encloses an area about 305 m by 274 m. In the northwest part of the central enclosure is a shallow hollow 3 m in diameter and waterfilled which may have been the spring-water supply of the fort. The interior was trenched in 1845 by Warden, who notes that below 'rectangular walls and mounds were found in the original soil holes dug out, some round, some triangular and the greater number oval, varying in size from 7 inches to 18 inches in diameter, about 1' deep, filled with black matter consisting of dark-coloured earth, small pieces of bones, seemingly of sheep, completely calcined and little bits of wood burned to charcoal.' Neither pottery nor metal was found during the excavation. With no real evidence to go on it is almost impossible to interpret the structural phases of this site but there may be at least three, with the innermost enclosure being the last. It may be that not all the gaps are entrances, Feachem states the possibility that they may result from incomplete construction by sections. Though the fort is always referred to as 'Brown Caterthun' this name actually applies to the hill (Name Book 1858), although its derivation includes 'cathair', a circular stone fort. The meaning of the '-thun' part is not known. Detached lengths of slight banking and ditching outside the principal suite of defences recorded by Feacham may correspond to an unfinished scheme to encompass parts of the southeast shoulder of the hill within the fortified zone. The fort that crowns the summit of the Brown Caterthun commands impressive views across Strathmore. The defences present a remarkable array of earthworks, some slight, others more substantial, and thus can be shown to reflect several periods of construction. The order in which all seven lines of earthworks were constructed, however, cannot be demonstrated without excavation, and for the purposes of this description they are lettered from the innermost outwards (A-G). The innermost (A) is defined by little more than a shallow groove defining the north side of an enclosure measuring about 30 m in diameter. The innermost of the ramparts (B) has been reduced to a low stony bank enclosing an area measuring about 88 m from north-northwest to south-southeast by 55 m transversely. Five gaps are visible in the rampart, but it is not known how many of them are original. Set between 52 m and 23 m downslope from B there are two concentric lines of defences (C and D) enclosing an area measuring about 192 m from north to south by 143 m transversely. The inner (C) is a substantial rampart which has several lines of outer face visible and a few internal quarry-pits, while the outer (D) comprises twin ramparts reduced to little more than scarps. Nine entrances are visible in rampart (C), all of them matched by gaps in the twin ramparts (D) beyond them. The latter, however, have an additional gap at (H), which appears to be the remains of an entrance blocked by rampart (C). Eccentrically placed between 10 m and 43 m beyond these ramparts there are two further lines of defence (E and F) which follow roughly parallel courses. The inner (E) is a thick rampart flanked by shallow internal quarry-pits for its entire circuit. The outer (F), is represented by a rampart with an external ditch and counterscarp bank, it too is intermittently flanked by internal quarry pits. Nine entrances through these defences are visible, most having worn hollows dropping down between the rampart terminals and three give the impression of an entrance passage flanked by low banks linking the two lines of defence. On the southwest, (J), one of the quarry-pits behind rampart (E) appears to cut a hollowed track which drops down from an entrance through ramparts (C and D). The seventh line of earthworks (G) contours round the spur to the southeast of the fort and, where best preserved, comprises two low banks with a medial ditch. Three separate defensive schemes may be identified within the earthworks, one represented by rampart (B), a second by ramparts (C and D) and a third by ramparts (E and F). The evidence visible at (J and H), however, only allows the defences of the second and third schemes to be placed in sequence. This evidence indicates that ramparts (D) were superseded by (C), which was followed by the construction of (E and F). Nonetheless there is no evidence of any robbing along rampart (C), which may well have continued in use after the addition of (E and F). These two outer lines of defences were almost certainly constructed at the same time, as can be seen by an examination of the dog-leg in the ramparts on the east side of the fort. The origin of this curious arrangement probably lies in a serious error in the planning and execution of the work. For the most part the outer defences follow the contour, but at (K) they turn abruptly upslope and cut across the southeast spur of the hill. The slight earthwork (G) apparently continues this line along the contour. Whether (G) is a marking out earthwork is impossible to determine, but it appears that the builders of (E and F) took a short cut over the spur to shorten their perimeter, but failed to achieve the correct alignment when they met the ramparts under construction on the (E). Both lines of defence make abrupt changes in direction here, but faint scars (L, M and N) possibly derived from marking out or the first stages of construction, continue their lines. The relationship of the innermost rampart (B) and the inner enclosure (A) to the rest of the defences is unknown. The poor state of preservation of rampart (B), however, suggests that it was robbed to provide stone for the comparatively undisturbed rampart (C). The remains of the inner enclosure (A) are similar to those identified in the White Caterthun fort (NO56NW0017) and are comparable to the slight earthworks derived from palisaded enclosures in the Border Hills. Further rescue and research excavations were undertaken in 1995, at which time it was noted that the site was suffering severely from the effects of rabbit burrowing. Only trenches with results of particular interest are detailed below. Trench 23 was excavated across a shallow depression on the summit of the hill, generally regarded as the site of a spring. A rock-cut bowl circa 3 m in diameter by 0.8 m deep was revealed, with two phases of use were indicated by a recutting of the bowl. The recut feature was filled by a silt rich in burnt grain and charcoal, possibly indicating a function associated with crop processing. Trench 20 was excavated across the south entrance and immediate interior of the inner enclosure, extending Trench 6. The enclosure was originally defined by a low upcast bank, into which two concentric and parallel palisade slots were cut circa 1 m apart. These palisade slots defined a gated entrance-way circa 2 m wide. A primary layer of well-laid cobbling was revealed below the enclosing bank. A spread of rough cobbles was defined within the entrance-way and extended within the enclosure. A number of pits, post-holes and lengths of a curvilinear slot identified within the enclosure probably relate to structural remains, but no coherent patterns could be observed. Trench 19 investigated whether the surface indications of a hut platform, one of several on the upper east slopes of the hill, was confirmed by sub-surface remains. The truncated remains of 11 post-holes and two discontinuous arcs of narrow slots were recorded, which probably represent elements of a timber structure. Hearth waste and pottery were recovered. Trench 17 revealed the largest rampart encircling the hill to be very similar in constructional detail to that identified in Trench 5, comprising a stone wall surmounted by a scorched turf or earth cap. An alignment of four small post-holes ran beside the inside face of the wall. Samples of alder and willow charcoal recovered from the collapsed breastwork in Trench 5 have provided radiocarbon dates. Trench 16 examined an entrance passage through the largest encircling work, expanding Trench 8. The rampart terminals defining the passage were of similar construction as identified in Trenches 5 and 17. The cobbled entrance passage was circa 2.7 m wide and was lined by six post-holes arranged in three opposing pairs, the central pair being the largest. Two parallel and intermittent palisade trenches circa 3.5 m apart approached the entrance from the east (exterior). Parts of these alignments were sealed below the rampart terminals, indicating that the entrance-way had two structural phases. Trench 15 investigated a section of the rampart previously examined in Trench 2, revealing it to be here composed of a series of mixed subsoil dumps and grey, silty, charcoal-rich deposits revetted on the exterior by a boulder face backed by cobbles. A curvilinear alignment of cobbles ran beneath the rampart core, and either represents part of the rampart construction itself or the remains of an earlier structure. Trench 13 extended Trench 3 to investigate the whole of an entrance and adjacent rampart terminals of the second outermost encircling work. The rampart was of similar form to that revealed in Trench 2, although here two discrete levels of burnt timbers were identified, the lower of branches and the upper of small roundwood. A rock-cut terrace lay immediately outside the rampart, increasing the height of the external face of the rampart. Four rock-cut post-holes defined the position of a gateway. A secondary stone alignment and a low upcast bank defined an avenue leading uphill to the entrance. Samples of birch and alder charcoal obtained from the timber layer within the rampart excavated in Trench 2 have provided radiocarbon dates. Trench 14 investigated a section of the outermost rampart and rock-cut ditch previously examined in Trench 1. These earthworks were structurally as identified in Trench 1, although there was possible evidence of a recut within the upper ditch fills and of a bedding trench on the crest of the rampart. The slight remains of a counterscarp bank and a curvilinear palisade slot were located immediately outside the ditch. This latter may be part of a structure truncated by the rampart and ditch. A sample of hazel charcoal obtained from the buried turf layer sealed below the rampart in Trench 1 has provided a radiocarbon date. Trench 12 expanded Trench 4 to investigate the whole of the E entrance through the outermost encircling works. The cobbled entrance passage was revealed to be 2.8 m wide, and to contain no certain evidence for a gate structure. The rampart and ditch defining the north side of the entrance inturned markedly, and were abutted by a secondary bank extending uphill towards the Trench 13 entrance. A cobble-filled gully ran between the two ditch termini, probably representing a drainage feature. In March and April 2011, excavations were carried out by Kirkdale Archaeology in two areas (centred on NO 5550 6673 and NO 5556 6672) to determine the extent of damage to the monument incurred as a result of fence maintenance work, and also investigate the nature of the monument in these locales with the intention of recovering dateable samples along with other archaeological and environmental evidence.
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