5. Subsidence of Crannog.—In discussing the question regarding the Lochlee crannog I had to contend with an element of very great uncertainty, viz., the impossibility of ascertaining how much of the apparent sinking of the crannog was due to the rising of the level of the lake in consequence of the filling up of the bed of the outlet. This doubtful element is, however, entirely eliminated from the problem as it is presented to us at Lochspouts. Whatever alterations may have taken place in the position of the outlet, one thing is certain, that the tendency could never be to raise the level of the lake. Hence, if we can fix on the position of the natural outlet when the artificial cutting was made, the minimum amount of subsidence of the crannog resolves itself into simply measuring the height of this point above the present surface of the log pavement. I use the word minimum, because, to determine the actual amount, other two elements have to be considered, both of which tend to magnify the amount of subsidence, viz. (1) How much the surface of the crannog was originally above water; and (2) the amount of lowering of the lake, due to frictional erosion of the water at the outlet, during the interval between the founding of the crannog and the date of the artificial cutting of the rock. For the present I entirely exclude both these elements; so that the solution of the problem depends on the practicability of ascertaining the height of the lowest natural outlet above the level of the log pavement. I believe the primary outlet was at the extreme east end of the barrier, where it disappears into the hillside. Here is to be seen a large deep opening, naturally scooped out of the rock; the lowest portion of which is only 161⁄2 feet above the present level of the lake. It was, however, found, on measurement, that a lower natural outlet was just in the site of the present artificial cutting. The upper portion of the latter is wide, but about 14 feet from the running water it contracts into a narrow channel with perpendicular sides, and the sole difficulty is to determine where nature ended and art began. If we suppose that the whole of this narrow channel was artificially cut, then the lake must have been lowered to a corresponding extent. This, however, may be beyond the mark, as in the course of time the water itself would make a similar channel. After repeated and most careful inspections of this spot, I am inclined to fix the minimum amount of cutting at 10 or 12 feet. Based, therefore, on the lowest estimate, the original surface of the crannog must have subsided over 10 feet, as it is now just on a level with the lake water.
Relics.
No inference worthy of note could be drawn from the relative position of the relics found on this crannog. They were interspersed amongst the débris, chiefly around the fireplaces and over the area of the log pavement, at a depth varying according to their distance from the centre of the mound, but none more superficial than about 18 inches from its surface. Though in point of number and variety the general collection is not equal to that from Lochlee, it is scarcely inferior to it in archæological importance. Following the system of arrangement adopted in the latter, I have described the various articles under the several heads suggested by the respective materials of which they are made.
I. Objects made of Stone.
Hammer-Stones.—These implements were in great abundance, forty of which were collected and transferred to Kilkerran House. According to the principle of classification hinted at in the description of those found at Lochlee, which is based exclusively on their shape and the position of the markings, they fall to be arranged in three groups.
First, Two are somewhat flat and circular, about 31⁄2 inches in diameter, and exhibit markings all round the edge.
Second, Three, similarly shaped, have the markings on the flat surfaces alone, and appear to have been held when used with one of the flat surfaces in the palm of the hand.
Third, The rest are more or less elongated, and show wrought surfaces at one or both ends. The largest, made of a fine-grained dolorite, is beautifully polished, tapers slightly towards one end, and measures 7 inches long by 4 broad. A few more were of the same material; and Mr. J. Thomson, F.G.S., Glasgow, informs me that this rock is only found in situ at Ailsa Craig, but that water-worn pebbles of it are abundant along the seashore in the neighbourhood of Girvan.
Polishers.—Under this head I classify about a dozen pestle-like implements, notwithstanding that slight pounding markings were observed at the ends of one or two of them, because they are all over so smooth and glossy that they seemed to have been used rather for polishing or smoothing some soft material, than as hammer-stones. There are also about a similar number of flat polishers, varying much both in size and shape, one of which is triangularly shaped like a modern smoothing-iron. It measures 5 inches long, 41⁄2 broad at base, and 11⁄2 inch thick.
