[Illustration: FIG. 72.--Chapel near Shore of Head of Holland. Plan.] 15 feet 4 inches north and south inside. The north and south walls are 2 feet 6 inches thick, and east and west ends 3 feet 3 inches, and are of the red sandstone of the locality. There was a door in the south wall. Planned in 1870. (Fig. 72.) HALCRO CHAPEL, SOUTH RONALDSHAY. This is now wholly destroyed, and even the foundations taken out, but the measures were obtained by Mr. G. Petrie so soon after the removal of the latter that the thickness of the walls could be accurately determined. It was a parallelogram, 21 feet by 14 feet inside. The walls were 2 feet 6 inches thick. The place of the doorway was not ascertained. Planned in 1870. (Fig. 73.) [Illustration: FIG. 73.--Halcro Chapel, in South Parish, Ronaldshay. Plan.] ST. TREDWELL’S CHAPEL, PAPA WESTRAY. This chapel is situated on a little holm in a fresh water loch on the east side of Papa Westray. (Fig. 74.) It appears probable that a Pict’s [Illustration: FIG. 74.--St. Tredwell’s Chapel. Plan and Section.] house was constructed on this holm, and that the chapel was built on its ruins. This St. Tredwell is the same as St. Triduana, whose day in the Roman calendar is October 8th. She is not mentioned by Alban Butler. The chapel was much frequented in its day, and many benefits were said to [Illustration: FIG. 75.--St. Tredwell’s Chapel. Plan and Elevations.] be obtained from the Saint by her devotees. It is a plain parallelogram (Fig. 75), 20 feet 3 inches east and west by 13 feet 10 inches north and south inside, and stands west by south and east by north. There is a narrow doorway near the west end of the south side. Only the lower portions of the walls remain, except at north-west angle, which measures 8 feet high; but here we have, as usual, the unfortunate information that within memory the east gable and south wall were standing. The thickness of the wall on the north is 3 feet 11 inches; east, 4 feet 2 inches; south, 4 feet 3 inches; and west, 4 feet 9 inches. It is stated that there was a window in the east end, and that the doorway was flat headed. No trace of a window remains, and only about 3 feet 6 inches of the door jambs remain. These have a rebate into which a door is fitted, but whether in a wooden frame or not cannot be ascertained. The original floor appears to have been 10 feet above water level. There is no means of assigning a date to the building, but the difference in the thickness of the walls makes it possible that it has been altered since its first erection. Planned 1870. CHURCH AT SWENDRO, ROUSAY. This is in a graveyard, close to the west shore of Rousay, about a mile north of Westness. It consists of a long parallelogram, and, but for a stoup near the door, and apparently an ambry near the east end, might be taken for a post-Reformation building. It has been used till within memory. It stands about east and west. (Fig. 76.) It is 52 feet 11