Field Visit

Date 2 July 1958

Event ID 925140

Category Recording

Type Field Visit

Permalink http://canmore.org.uk/event/925140

RCAHMS Marginal Land Survey

Fort, Cnoc An Duin.

The hill named Cnoc an Duin, which attains a height of904 feet above sea level, rises steeply for 450 feet from the left bank of the Balnagown River where this runs through Strathrory on its way to enter the Cromarty Firth at Nigg Bay, six miles to the ESE. The hill commands most of Strathrory into which it protrudes from the massif immediately to the N, and at the same time dominates the Glen of Scotsburn and Glen Aldie through which the Aldie Water flows to Tain and the Dornoch Firth.

The summit of the hill consists of a comparatively flat oval area measuring about 730 feet from E to W by about 250 feet transversely. The flanks of the hill slope steeply down from this to S and W towards the river, but to the N there is a more gentle descent of less than 50 feet .to a narrow marshy valley which connects Cnoc an Duin to the massif beyond. To the E however the summit plateau is cut off from the neighbouring part of the bill by a steep-sided rocky gorge of striking appearance which runs from N to S to form a gash a quarter of a mile in length and up to 150 feet in breadth thus effectively isolating the part of the summit just described.

The construction of a hill fort was begun, but not completed, on the summit plateau which, cut off by the gorge, formed a natural defensive promontory. The inner line was evidently to consist of a stone wall10 feet in thickness, for starting near the brink of the S lip of the natural gorge a substantial line of boulders runs W along the N margin of the summit plateau for a distance of 770 feet to terminate near the S extremity. For the most part the line of boulders appears as a heavy mass of tumbled blocks and slabs which is spread to a width of about 10 feet or12 feet., the edges of the mass appearing to be overlain in places by peat. The westernmost stretch, 170 feet in length, has several interesting characteristics. The amount of stones in this sector appears to be greater than that visible further E, while stretches of built faces begin to be visible above the heather at irregular intervals on either side of the mass of boulders. Some sections of faces up to eight courses in height can be seen but in all cases these have fallen backwards to a greater or lesser degree into the loose rubble at their rear which formed the core of the wall. At a point 40 feet from the termination of the line of the boulders there is a ruinous but clearly perceptible transverse face which runs across to unite the inner and outer faces. Beyond this the lowest course of the outer face can be seen to continue without interruption all the way to the end; that of the inner face only resumes after a gap of about 5 feet, but thereafter it too runs to the end, It is notable that from the transverse face to the end the wall consists of an inner and an outer face of one or two courses in height between which are placed enough boulders to fill in the space but not to form a pile or to rise above the low faces. There can be no doubt that this final. stretch of 40 feet represents an early stage in the construction of the wall, and that the proceeding was apparently first to lay the lower course of the facing stones at the required distance apart, then to fill in the space between them with boulders, and so to erect the wall, in the form of built faces with a rubble core, on the foundation thus prepared. It is remarkable that, when the embryo wall ends abruptly at the W end of the summit plateau, the course it would presumably have proceeded to follow along the S edge of the plateau is not marked out either by a marker trench (Little Conval) or by a rickle of stones (Durn Hill). It is possible that perishable objects such as wooden pegs were used in this case.

Apart from the cross-face in the NW arc of the wall which has been described above, the only other gap in the line of boulders is near the E end. The line springs from near the lip of the natural gorge, as already mentioned, but after a distance of only 60 feet in a straight line the boulders cease. There ensues a gap of some 20 feet, on the far side of which the boulder line resumes at a different angle. It is possible that the gap was designed to form the basis of a main entrance but the alignment of the wall on either side of it cannot readily be explained.

The outer line of defence also appears in an incomplete form. It consists in essence of a linear excavation designed to follow the wall, or the crest of the summit plateau, at a distance varying from 40 feet to 70 feet. At no place was it advanced to a stage nearing completion, but sufficient work exists to show that the final spoil was to be thrown outside the ditch or terrace and that the larger boulders were being collected above the inner lip. . All along the N flank of the hill, from the lip of the gorge for a distance of about 800 feet, this line of defence appears merely as a shallow terrace dimly perceived in the long and deep heather. There are several minor interruptions along it, and two major ones but most if not all these probably represent the boundaries between the work of different gangs. At the end of this stretch the line begins to turn through SW to S, and thereafter for almost its entire length it is not only free from heather but runs along the steeper flanks of the hill. A gap in the S arc covers the place in the inner line of boulders where the transverse face crosses it. The gap consists of a causeway in the excavated ditch or terrace some 12 feet in width, the N side of it being well-defined because an attempt has been made to collect stones and boulders and to form them into a line of transverse facing about 15 feet in length. This spans the end of the excavation and likewise forms a termination to the outer line of gathered stones, and may even have run on to the inner line. It is now so ruinous, however, that no precise description can be given. Beyond the the excavation and the collections of boulders and rubble both above below it continue round the SW and S faces of the hill. Traces of gang work appear all along it, and for a considerable stretch the excavation cannot be traced at all. In the last 200 feet before the gorge is reached again the stones and rubble collected outside the excavation begin to form a low mound while the amount of boulders on the inner side increases. Just before meeting the lip of the gorge the outer defence is again covered with long heather, but it is probable that the outer mound turns up to the N to terminate on the lip of the gorge. There is nothing to show that there was ever any defensive line on the crest of the gorge.

The interior is covered with peat and heather, and the only definite feature visible within it is what appear-s to have been a small water-hole. The hole, about 2 feet in diameter, was choked with stones at a depth of 2 feet and dry on the day of visit. It occupies the bottom of a shallow depression itself about 2 feet deep and 10 feet in width in which a penannular wall one course thick stands to a height of 4 feet. The wall is probably of no great age.

NH 696 769, OS Map ilv

Visited by RCAHMS 3 July 1958