Auchagallon Stone Circle is the remains of a Neolithic or Bronze Age burial cairn, surrounded by a circle of fifteen stones. The cairn and stone circle is situated on a slight ledge of a west-facing slope, overlooking Machrie Bay. The circle comprises fifteen blocks varying in height from 0.5 metres to 2.3 metres. The stones are of red sandstone, except two which are a pale grey granite. The circle has a maximum diameter of 14.5 metres.
In the centre is a large stone cairn. Antiquarians digging here in the 19th century found a burial cist in the centre, although there are no records of any other remains. Although the monument is now called a stone circle, it was probably built as a kerbed cairn.
References:Sigmaringen Castle was first mentioned in the year 1077 in the chronicles of Petershausen monastery. The oldest parts of the castle are concealed beneath the alterations made during the 17th and the 19th centuries. The secret of the earliest settlement built on this defendable rock will never be fully revealed: large-scale excavation work would be necessary, which the extensive land development renders impossible. Judging from the many Roman remains unearthed in the area around Sigmaringen, the 12th century keep known as the 'Roman Tower' could be traced back to a Roman predecessor.
The castle remains that have been preserved (gate, great hall and keep) date back to the Staufer period around 1200. The castle remains were integrated into subsequent buildings. The foundations of the castle buildings are to a large extent identical to the surrounding castle wall.
These remains give us a good idea of how the castle might have looked during the 12th century.