The first was South Ronaldsha; its length is between eight or nine miles, its greatest breadth, from Grimness head to Hoxa head, five miles and a half: At Hoxa head, upon an isthmus, I saw the resmains of what the Orkney people call a Pictish fort, on the supposition that it and such other forts were built by the Picts; but there is little reason to think that the Picts were ever in possession of any part of Orkney. This fort has been of a circular form, with a wallround it, and perhaps two, the one surrounding the other at the distance of about three feet. Some remains were still to'be seen of this double wall. The building is certainly the work of a rude and consequently early period. It does not appear that any kind of cement has been used to tie the stones together: They are laid one upon the other in their natural state, rough and unpolished, with little regard to art or symmetry. Its extent, as far as I could guess, did not exceed 20 feet diameter. The outer wall inclosed a considerable part of the small eminence on which the fort stood. This eminence has certainly been surrounded formerly by sea, and perhaps at no very distant period was still so at high water: For, to the north east of the eminence, there is to this day a small lake of sea water, which is only separated from the sea by a ridge of sand and pebbles cast up by the sea, and the ridge itself is not above twenty feet broad. At the foot of the eminence, to the north, is a small bay or landing places, and on a point of land on the north of the bay, facing the eminence, there has been another fort of the same kind with the one I have now described. This inclines me to believe, that the design of the forts has been to protect the shipping of the Norwegian rovers, who frequented these islands, and to spread an alarm by ssignals from the top of the fort. I was told that there were many such forts in the different islands: Some of them I saw ; their situation and structure have been exactly the same with the above mentioned one. They are all upon a rising ground close to the water edge, on small points of land projecting into the sea or lake nigh which they stand. I was likewise told, that human bones were found in the ruins of some of these towers, but I saw none; it would have been necessary to have dug up the stones and rubbish, which I had not an opportunity to do.