The Pembrokeshire Coast displays a greater variety of rocks and scenery than any equivalent area in Britain with over 250 miles of exposures.
The landscape is ancient with nearly all the rocks underlying its land surface formed before the end of the Carboniferous period some 290 million years ago.
The oldest date back 600 million years and can be found on the Treginnis Peninsula, south west of St Davids. Rocks younger than 290 million years old have been lost, largely as a result of weathering and marine erosion.
Broadly, in geological terms, the county can be divided into north and south. The rocks in the north are of Precambrian and Lower Palaeozoic age.
Many are made from sea floor sediments, although there are also some igneous rocks.
They were all laid down before the Caledonian mountain building period, which ended about 400 million years ago.
As a result they show a south west to north east grain. The folds and faults seen in the rocks of the north, as at Ceibwr Bay, were created by this event.
Rocks in South Pembrokeshire are younger with most belonging to the Upper ie later Palaeozoic Era.
The most common are Old Red Sandstone and Carboniferous Limestone formations, as well as coal measures of the South Pembrokeshire coalfield.
The majority are sedimentary but some igneous rocks can be found along the southern shore of St Bride’s Bay.
The folds and faults in the rocks of the south, like Cobbler’s Hole at St Ann’s Head, were created during a later period of mountain building called the Hercynian Orogeny.
Here the grain of structures is almost east west.
The diversity of the coastal landscape we see today is the result of geological processes and actions such as glaciation, river weathering and marine erosion on this wide variety of rock types.
Discover more about the Pembrokeshire Coast Path
Each section of the Pembrokeshire Coast Path has a story to tell, and archaeology can help to unravel some of these tales.
Countryside and Landscape
The Pembrokeshire Coast Path winds its way across a variety of landscapes, from high cliff tops and secret coves to sweeping estuaries and wide sandy ...
Beaches and Tides
The highest tides cover parts of the Coast Path for an hour or so. It is a long extra walk to go around these. It is best to just wait until the water...
Dogs on the Coast Path
Information on walking with your dog responsibly on the Pembrokeshire Coast Path National Trail.
When you walk along the Pembrokeshire Coast Path National Trail you are not just walking through a geographical landscape, you’re also taking a jour...
Maintaining the Coast Path
In maintaining the Coast Path, the Pembrokeshire Coast National Park Authority aims to balance the quality of the walking the experience with the safe...
North to south or south to north?
Most of the guides, are written as if one is walking from St Dogmael's to Amroth. The stiles and gates have numbers on with number one being near Pen ...