Large Iron Age roundhouse Explore the remains of the large Iron Age roundhouse discovered at Birnie. Above: Artist’s impression of the house, with a central fire-pit and two floors. Left: Detail of the eroded area where the animals were stabled, with traces of a cobbled surface. The grooves in the background are modern plough marks which have cut into the archaeological remains. Right: Large Iron Age roundhouse, with a circle of holes for posts to support the roof. The dark curving shape is where the animals were stabled. Life inside the roundhouse.