Cardigan’s hills, valleys and coastline demonstrate a diverse range of physical features that reveal its complex geological history. The area’s rocks are mostly mudstone, deposited in a deep ocean basin about 450 million years ago. Associated locally with the mudstone are beds of hard sandstone, which can be found at Poppit Sands. These are often between one and two metres thick but elsewhere may be only a few millimetres thick. They were deposited as mud and sand on the sea bed but over time became deeply buried. Approximately 410 million years ago the deposits were squeezed and folded by massive earth movements, which eventually changed the mudstones into slate.
These folded rocks are best seen along …