The entrance is covered with flat stones, and is narrow, because it was necessary that the stones which lie over it, should reach from one wall to the other; yet, strait as the passage is, they seem heavier than could have been placed where they now lie, by the naked strength of as many men as might stand about them.  They were probably raised by putting long pieces of wood under them, to which the action of a long line of lifters might be applied.  Savages, in all countries, have patience proportionate to their unskilfulness, and are content to attain their end by very tedious methods.

If it was ever roofed, it might once have been a dwelling, but as there is no provision for water, it could not have been a fortress.  In Sky, as in every other place, there is an ambition of exalting whatever has survived memory, to some important use, and referring it to very remote ages.  I am inclined to suspect, that in lawless times, when the inhabitants of every mountain stole the cattle of their neighbour, these inclosures were used to secure the herds and flocks in the night.  When they were driven within the wall, they might be easily watched, and defended as long as could be needful; for the robbers durst not wait till the injured clan should find them in the morning.

The interior inclosures, if the whole building were once a house, were the chambers of the chief inhabitants.  If it was a place of security for cattle, they were probably the shelters of the keepers.

From the Dun we were conducted to another place of security, a cave carried a great way under ground, which had been discovered by digging after a fox.  These caves, of which many have been found, and many probably remain concealed, are formed, I believe, commonly by taking advantage of a hollow, where banks or rocks rise on either side.  If no such place can be found, the ground must be cut away.  The walls are made by piling stones against the earth, on either side.  It is then roofed by larger stones laid across the cavern, which therefore cannot be wide.  Over the roof, turfs were placed, and grass was suffered to grow; and the mouth was concealed by bushes, or some other cover.

These caves were represented to us as the cabins of the first rude inhabitants, of which, however, I am by no means persuaded.  This was so low, that no man could stand upright in it.  By their construction they are all so narrow, that two can never pass along them together, and being subterraneous, they must be always damp.  They are not the work of an age much ruder than the present; for they are formed with as much art as the construction of a common hut requires.  I imagine them to have been places only of occasional use, in which the Islander, upon a sudden alarm, hid his utensils, or his cloaths, and perhaps sometimes his wife and children.

This cave we entered, but could not proceed the whole length, and went away without knowing how far it was carried.  For this omission we shall be blamed, as we perhaps have blamed other travellers; but the day was rainy, and the ground was damp.  We had with us neither spades nor pickaxes, and if love of ease surmounted our desire of knowledge, the offence has not the invidiousness of singularity.