Before chronicling the final triumph of the cave explorers in 1859, we may briefly note another series of investigations which was being carried on at the same time, and which also shared in the work of throwing light on the shadowy figure of prehistoric man. This was the excavation of crannogs and lake dwellings. [Sidenote: =Irish Crannogs.=] In 1839 Sir W. R. Wilde explored some of the Irish crannogs, or semi-artificial islands, usually made of layers of stone, logs, sticks (the so-called fascine dwellings), resting on _cluans_ or islets in the Irish lakes. The first crannog explored was that at Lagore, famous in ancient times as Loch Gobhair, near Dunshaughlin, co. Meath, and mentioned in the _Annals of the Four Masters_ as having been plundered in the ninth and tenth centuries. It was originally discovered by accident. Some labourers, when clearing out a stream in the neighbourhood, came across very numerous bones, and also a vast collection of objects of all descriptions, warlike and domestic, made of stone, bone, wood, bronze, and iron, and a few human remains. The next crannog to be disclosed was one in Roughan Lake, near Dungannon; and thereafter more and more came to light, until in 1857 forty-six had been recorded. The crannog finds, and the depth of the deposits, indicated great age; and Sir William Wilde at once recognised their significance in determining the history of early human occupation in the island. This evidence was strengthened by the discoveries shortly afterwards made in Switzerland. [Sidenote: =Swiss Pile-Dwellings.=]