“It would be a serious mistake, however, to place in the same category the Island of Bute, where freestone (red) occurs locally, and the best qualities of rock on the adjoining mainland. Freestone was in common use with the Romans both for monumental work and building, and it is precisely this simple splayed form of base which is most frequently to be found. As to its use in Celtic work there may be cited Cruggleton Chapel (Vol. I. pp. 212-215), about three miles from Whitherne Priory, which by every criterion is extremely primitive, much earlier than the priory, and also Celtic, founded most probably by the Carrols or M‘Kerlies, who wrested the castle from the Norse jarls. There the base, which has been laid on the grass level, has a base course precisely similar to that of St. Blane’s, with rubble above and below. In fact, the entire building is rubble, except the dressed work and the chancel arch. It is not freestone, but silurian grit, from the Stewartry shores. It is no doubt later in date than St. Blane’s, but Bute is much more favourably situated for freestone than Wigtonshire, where it is locally non-existent, and the combination of rubble and hewn work at Cruggleton is a striking testimony to the difficulty even of obtaining grit. “The second head refers to the mode in which the strings and base courses would be stopped against the rubble. According to my drawings there has been a string on the north side of the nave, which dropped nearly two feet, has also run along the ashlar work of the chancel, but only two feet or so of it remains. On the south side this feature is entirely destroyed. The base, both on north and south sides of the nave, returns round the chancel gable and _there terminates_. Whether they were dropped also I cannot tell, as these drawings were made previous to the later reduction of the soil to the original level.[269] An important point in this junction of rubble and ashlar walls must be noted, viz., that while the ashlar walls are 2 feet 7 inches thick, the rubble wall on the south side is only 2 feet 5 inches, and that on the north 2 feet 3 inches. The walls meet flush on the outside, and on the inside the ashlar corner is splayed off in accommodation to the thinner rubble, and those who managed thus would find no difficulty in such trivialities as a string or a base.