Ffynnon Beuno and Cae Gwyn Caves Tags: Site Of Special Scientific Interest.Ffynnon Beuno and Cae Gwyn Caves is a Site of Special Scientific Interest in Denbighshire Wales.Human tools have been found on the site dating back to around 36000 BC and a mammoth bone has been dated back to 16000 BC. thumbnail country United Kingdom location United Kingdom Learn more... Loading...