NOTE: Photos of the Pictish Beast were found on the internet with a search for "Pictish Beast public domain". If I recovered any photographs that were not public domain I did so inadvertently, and I apologize for their use.
Bentley, Mary and Ted,
1981 Gabriola: Petroglyph Island, Sono Nis Press, Victoria, B.C.
2017 Lost Dark Ages Fort Found in Scotland, January 22, 2017, Live Science, http://www.livescience.com/57591-lost-dark-ages-fort-found-scotland.html