Earth Houses, the general name for curious pre-historic structures, found chiefly in Scotland, but occurring also in Ireland and in Cornwall, whence their Celtic origin has been inferred. The general plan is a curved subterranean gallery, in some cases more than 60 feet long, widening from the opening, and sometimes chambered. The walls are lined with dry masonry, converging towards the top, which is covered in with large unhewn slabs, these being but little below the surface and often uncovered by the plough. Some of these structures, from the relics found in them, appear to have been occupied down to the period immediately after the Romans quitted Scotland. They may have been receptacles for plunder, or places of shelter from the inclemency of the weather before houses were built, or of concealment from an enemy. It is noteworthy that Tacitus (Germania, xvi.) describes somewhat similar structures as existing among the Germans.