Nothing impresses one so much with the fact of the former importance of Arran, owing to the very central position it occupied between the various tribes who had settled in prehistoric times on the mainland or on the islands around, than the green mounds which mark the remains of its wonderful chain of camps, forts, or dunes. In these the natives kept watch over the dividing seas for white sailed boat or narrow canoe or coracle, and when they saw the invading force it was to such great camps as that of Drumadoon or Glen Eas (Ashdale), or Tor Caisteal they brought their women and their other wealth. They belong to the greater fortresses of the coast, but besides these, everywhere, in every glen, there were small forts from behind whose walls no doubt arrows could be shot in safety at the enemy who dared to enter these fastnesses. From them in every case, I know, a view is obtained of the entire glen. A good example is that in Glen Cloy, in which Bruce is said to have kept watch for the soldiers of Edward. From it one can see the whole of the glen. At the point at which Glen Easbuig and Glen an't Suidhe meet, to the north of the Shisken road, is the site of another fort which must have commanded a splendid view of the Vale of Shisken.

DRUMADOON

Of the greater forts, that of Drumadoon is by far the most interesting. Splendidly situated on the sea cliffs some 200 ft. above the beach, its features can still be made out. Its wall, 10 ft. in thickness, protected a space of some acres in extent. Its commanding position and its excellent defences rendered it impregnable, and a safe sheltering place for the whole district of Waterfoot, which must have been, from its flatness, so exposed to the assaults of enemies from over seas.

TOR CAISTEAL

The next link in the chain of coast defences is Tor Caisteal, near Sliddery, a few miles farther south. This fort is circular, and 160 ft. in circumference, its walls were some 6 ft. thick, and the approach to its entrance was protected by a smaller fort or outwork. The hill on which the castle was built is said to be artificial. The men who constructed it showed skill and intelligence, which prove them to have been far above the condition of mere savages.

GLEN ASHDALE

The fort or camp of Glen Ashdale occupied a fine position overlooking the great glen. The walls showed a thickness of 25 ft., and were formed of huge sandstone and granite blocks skilfully put together, and enclosing a space of 290 ft. or thereabouts. The glen itself is in point of richness of foliage and the splendid colour of the sandstone cliffs exceedingly fine, and very different in character to the wild glens of the north. The waterfall is the highest in the island.

KING'S CROSS

At King's Cross, close to the monolith which, tradition says, commemorates the embarkation of Bruce and his followers for the Carrick coast, is the site of a small round fort, 15 ft. in diameter, behind which the natives could no doubt defend the landing-place.

DUN FION

Dun Fion, on the other side of Lamlash Bay, was one of the island's chief defences, like Tor Coille. It stands some 600 ft. above sea-level, on the hill above Clauchlands Point, and its wall of 5 ft. in thickness enclosed a space of 140 ft. The walls are said to have showed signs of vitrefaction, which, Sir George MacKenzie suggested, was caused by the beacon fires lit in these forts from time to time. The walls being composed of porphyry and sandstone would, it was suggested, be fused by a very moderate heat. As a look-out station, the position of Dun Fion is one of the best in the island. No hostile galley could approach from north or east without being noticed, and when the help of others was needed the beacon from Dun Fion could be seen far and wide, at the small fort at King's Cross to the south, at the great one by Brodick and the small one of Springfield to the north. From these would leap up similar beacon fires to warn the good folk all round the island, and across at Carradale and Dalaruan in Kintyre and Bute, whence the kinsmen of the islanders, and the Somerledian chiefs, could send them aid.

CRAIG NA CUIROCH

Out of the great fort of Brodick rose the historic castle which has been, I believe, oftener attacked and burnt than any fortress of the West Highlands. From Brodick the next fort, going north, is the old one overlooking Sannox Bay, and from there the coast needed no defence, being so precipitous, till we reach Loch Ranza, and find the remains of the great fort on Craig na Cuiroch. The defence of a place like Ranza must have been comparatively easy; indeed, it must have been impossible for an enemy to approach it, for the natives could assail the invaders from the surrounding hills.

The real weakness of Arran lay in the Machrie Moor and Shisken districts, where landing was easy, and the wide plain was difficult to defend with a small force. The interior of the island would, however, afford a succession of death-traps to any troops, and it is pretty certain that they were seldom if ever assailed by the Norsemen or any other invaders, and certainly never held by them. The purely Gaelic character of the place-names of these parts, save in one or two great passes like that of Glen Hamadel, corroborate this conclusion.

TORNANSCHIAN

The list of forts, small and large, is by no means exhausted, showing clearly that the island was well populated and strongly held in old times. So strong were the defences that the old duns were probably in use for a thousand years, each succeeding generation finding them of service, just as the followers of Bruce found Tornanschian, the "stalwart place" in Glen Cloy, useful at need. It was undoubtedly a strong place ; even as late as 1772 Pennant says: "A mile beyond Kil-michael is Tornanschian Castle, surrounded by a great stone dike. Here Robert Bruce sheltered himself for some time." Pennant also saw "five earthen tumuli there in a row, with another outside of them. On that of another is a circle of stones, whose ends just appear above the earth. Probably," he adds, "the memorials of some battle."

In the fifteenth century we hear of the Arran lairds strengthening the defences of the island on account of the raids of the Kintyre clans. It is probable that the old forts at Drumadoon and Torcastle, Glen Ashdale and Dun Fion, were then still in use.