To add to the difficulties of dealing with the subject of crannoges, they were successively occupied for many centuries. They are mentioned in the most ancient Irish legends, and even in the sixteenth century they served as refuges for the kings of the country in the constant rebellions that took place. The objects taken from the lakes belong to very different epochs, and it is impossible to say anything positive as to the time of their construction. A but found in Donegal may, however, date from an extremely remote age.21 It rested on a thick layer of sand brought front the neighboring shore, and was covered over by a bed of peat slot less than sixteen feet thick. Since the hilt was deserted by man the peat had gradually accumulated till it had at last invaded the dwelling itself. The but included a ground-floor, and one story about twelve feet long by nine wide and four high. The walls consisted of beams scarcely squared, joined together with wooden mortices and pegs. The roof, which was probably flat, consisted of oak planks, the spaces between which had been filled in with mortar made of sand and grease. On the ground-floor lay several flint implements, showing no signs of having been polished, a quartz wedge, and a stone chisel, which had evidently seen long service. This chisel, the discoverers say, corresponded exactly with the notches around the mortices. A regular paved way, formed of sea-beach pebbles placed on a foundation of interlaced branches, led up to a hearth made of flat stones measuring some three feet every way. All about lay fragments of charcoal and broken nuts, the latter partly burnt. Another but, with an oak floor resting on four posts, has recently been discovered in County Fermanagh, beneath a deposit of peat about twenty feet thick. No trace of metal has been found in either of these Irish buts, and the thickness of the peat beneath which they lay is another proof of their great antiquity. One serious objection, however, is this: Were the Irish sufficiently advanced in prehistoric times to be able to erect dwellings implying so considerable an amount of civilization? Crannoges are met with in Scotland as well as in Ireland, and excavations in Loch Lee have enabled explorers to make out their mode of construction. The Lake Dwellers began by piling up a number of trunks of trees in the shallower waters of a lake. They then strengthened these trunks with branches or beams about which the mud collected till the whole formed an islet. All about this islet, beneath the waters of the lake, were found various objects in stone, wood, and horn, as well as some canoes several feet long. Similar crannoges are to be seen on the lakes of Kincardine and Forfar, which Troyon thinks date from the Stone age.22 If he be right, and we should not like to make any assertion one way or the other, the bronze objects and the enamelled glass bowls found near these dwellings prove that they were occupied by several successive generations.