The nave survives as a whole, and contains six bays, divided by massive piers, and surmounted by a triforium and clerestory. There is a north porch, and two doorways from the cloister on the south side.
The oldest portion of the building is pronounced to be the eastern part of the south wall of the south aisle of the nave, where it adjoins the transept. This portion of the wall consists of three bays, containing the S.E. doorway from the cloister to the nave, and three pointed windows in the upper part. The doorway is of the transition style, and the windows above are simple in style, and are early pointed work—this part of the building probably dating from the first half of the thirteenth century.[387] The western portion of the south aisle of the nave and the whole of the south clerestory are evidently portions of the restored church of the fifteenth century.[388] The south aisle wall contains the S.W. and S.E. doors from the nave to the cloister.
The west end of the nave is in part amongst the ancient portions of the structure, and the western entrance doorway is thirteenth century work.[389] The aisle windows of the west front belong to the first pointed period. The upper portion of the west front above the two large windows is of considerably later date.[390] "The design of the west front, which contains above the door-piece two large windows, with pointed niches and small circles inserted between the arch-heads, is probably original, but the upper portion and gable, including the large traceried window, are doubtless part of the restoration of the fifteenth century. The tracery of the two central windows is peculiar, and may possibly be of the fourteenth century, but that of the large upper window is later, probably of the same period as the restoration of the interior of the nave. The tracery of the large upper window is a specimen of the late kind of design employed in Scotland in the fifteenth century."[391]
The interior of the west end of the nave exhibits the change of style caused by the restoration of the fifteenth century. The first or western bay of the main arcade is original, including the first arches (one on each side), the first pillars, and the arches between them, and the aisle responds. "These pillars and arches are of large dimensions and first pointed section, and appear to have been designed to carry western towers, but a part of their thickness has been cut off next the choir. A portion of the triforium wall, a piece of the string-course over the main arcade, and the corbelled vaulting shaft in the angle as high as the top of the triforium, are also parts of the original structure. The later work has been joined to the above old parts in a very awkward manner."[392] The cap of the west pier on the north side belongs to the first pointed work, while the corresponding cap on the south side and all the other caps belong to the fifteenth century restoration.[393] Except the west piers, the piers of the nave are of the clustered form, common in late Scottish work, and might be about the same date as the restoration of St. Giles, Edinburgh (which they resemble), in the early part of the fifteenth century.[394]
The triforium design consists of large segmental arches, the same width as the main arches, springing from short clustered piers introduced between them. It somewhat resembles the triforium of the nave at Dunkeld Cathedral. The clerestory is probably designed in imitation of that of Glasgow Cathedral, and is divided into two pointed arches in each bay. They spring from a series of clustered shafts with round moulded caps that are late imitations of early work.[395] The earlier part of the nave restoration, including the main piers and arches, and perhaps the tracery of the two lower windows of the west front, were possibly executed by Bishop Lithgow, who built the north porch, and the completion of the nave (the upper portions) was carried out in the time of Abbot Tervas—the middle of the fifteenth century. A peculiarity of the nave interior is a series of large corbels, which project from the spandrils of the triforium arcade, and the object of which was to enable a passage to be carried round the solid piers introduced between the windows. Each of the large corbels springs at its lowest point from the sculptured grotesque figure of a man or animal. They were mostly the work of Thomas Hector, a sculptor, who lived at Crossflat,[396] and whom the abbot retained for his skill in the art.[397] The employment of such grotesque figures was very much affected by the monks of Clugny, and was the occasion of a rebuke from St. Bernard. "What business had these devils and monstrosities in Christian churches, taking off the attention of the monks from their prayers." One of these figures near the west gable represents a man in a kilt, and Dr. Lees thinks that many worshippers in the Abbey in more modern times have in the midst of long sermons found relief in the contemplation of those curious carvings which the saint thus vigorously denounced.[398]
St. Mirin's Aisle was erected in 1499, and there is a large pointed window in the east end, having jambs with single shafts. It is divided into four lights, and the arch-head is filled with good simple tracery. Beneath the eastern window is a frieze of one foot eight inches deep between two cornices of eight inches deep, which were intended for sculpture. Three compartments, measuring four feet, at the north or right side, and seven compartments, measuring ten feet, at the south or left side, are carved and filled with sculpture. Dr. Lees says the reference of them to Mirin is clear beyond all doubt: "In the one on the extreme left we see Mirin's mother bringing him to St. Congal. In the next St. Congal putting the religious habit on Mirin. In the next Mirin taking oversight of the monastery of Banchor. There is after this a blank, and then we have certain sculptures relating to Mirin's encounter with the Irish king, who wears a crown on his head. In the first we have the servant of the King driving Mirin away from the door of the palace. In the next the King roaring with pain and held by his servants. In the next the Queen lying in bed with a picture of the Virgin on the wall, it being the custom to hang such before women during confinement. Then we have the King on his knees before Mirin, and afterwards Mirin received by him with joy. The next two sculptures represent the last two acts of the Saint—the brother looking through the keyhole and seeing Mirin illuminated by a celestial light, and the Saint restoring to life the dead man in the Valley of Colpdasch.... As they are evidently earlier than the date of the erection of the chapel, they have probably been transferred with the relics of the Saint from an older shrine. They look like twelfth-century work, but it is possible they may be even earlier."[399] The ceiling of the chapel is beautifully groined, and the east end, where the altar stood, is raised four steps above the western part. The west wall contains an outer doorway from the cloister court, and there is a traceried window above it. A large ambry adjoins the door in the outer wall. The chapel was connected with the south transept by two wide archways, now built up, and near the east end is a piscina, with three-sided head, like that in the choir.
There is a dormitory above the chapel, arched by stone, and the entrance is by a doorway in the middle of the south side of the arch. The apartment is lighted by two windows—one in the east gable, and the other in the west. In the west gable there is a private stair leading from the dormitory to the chapel, and the priest, who was bound by the charter to live at the chapel, doubtless occupied the sleeping-place above it.[400] The chapel at the Reformation was converted into a family burying-place by Claud Hamilton, the commendator, and various members of the Abercorn family lie buried in the vault below, the chapel belonging to the present Duke, and being under his control.
On the floor of this chapel there now stands an ornamental altar tomb, which was found lying in fragments near the Abbey by the Rev. Dr. Boog, one of the Abbey ministers, and who in 1817 had it brought within the chapel and erected again. It supports a recumbent figure, believed to be the effigy of Marjory Bruce, the daughter of Robert I. and the mother of Robert II. "The head of the figure is surmounted by a large cusped canopy, placed in a horizontal position, on the end of which is carved a crucifixion. The pedestal is carved with a series of Gothic compartments, in each of which there is carved a shield, enriched with heraldic blazons and figures of ecclesiastics. The panels at the west end contain—the first the fess chequé of the Stewarts between three roses; the third the fess chequé, surmounted of a lion rampant, and the central one, two keys saltierwise, between two crosiers in pale."[401] The chapel is famed for an echo, described by Pennant in his Tour Through Scotland,[402] but Dr. Lees regards the description of the far-famed traveller as either much exaggerated, or the strength of the echo has become diminished since his time. "When any number of persons are within the building, an echo is scarcely audible at all. It is amusing sometimes to see a group of people expending the strength of their lungs in vain by attempting to evoke it."[403]
Crosses seem to have been placed at intervals on the roads leading to the church. One of the south piers of the nave is called the Cathcart pillar, and has carved upon it a shield bearing the Cathcart arms. This is believed to be a memorial of Sir Allan Cathcart, who has thus been described by Barbour:—
A knycht, that their wis in hys rout,
Worthy and wycht, stalwart and stout,
Curtaiss and fayr, and off gud fame,
Schyr Allane of Catkert by name.