Portland’s quarrying history has created distinctive, almost lunar, landscape to explore, and one of my favourite spots is Kings Barrow Nature Reserve, located behind the Portland Heights Hotel off Yeates Road.. It is the site of former stone quarries abandoned over a hundred years ago. It covers over 12 hectares and is a great place for a wander as there is a wealth of geology, industrial archaeology and varied wildlife, as well as man-made gullies and tunnels to investigate. But take care as there are steep drops into old open rocky pits.
Look out for outcrops of unquarried rock – these will show you the geology of the area. The rocks in the quarry are Portland and lower Purbeck limestones formed in the late Jurassic, 140 million years ago. On the top, younger Lower Purbeck beds were formed in salt flats and lagoons that surrounded low, forested islands, where dinosaurs would have walked. Other layers are ancient soils like the Great Dirt Bed, complete with fossil trees. You can see evidence of these trees in the “Fossil Forest” which is near the A354 entrance. Thick mats of algae grew around the base of trees in muddy conditions, building up doughnut shaped tree burs. Around the quarry you will see deep single holes in some stone but these are not drill holes but cavities left by ancient trees.
Below the Purbeck beds is the Portland limestone series created in a shallow, tropical sea. These rocks are made of calcium coated layers of sand grains and fragments of shell. The top layer is ‘Roach Stone’, packed with easily seen fossils such as ammonites and casts of marine molluscs. These are best seen in some of the huge blocks that make up the drystone walls.
Below this are the Base and Whit Beds, that formed in deeper waters. These are the layers that are known for its first class building qualities and are famous across the world.
Dotted around the quarry are information boards giving you options of routes to follow.
As you walk around you will see clues to past quarrying activities. It’s easy to feel like a real explorer amongst the beaches of quarry waste, gullies and dry stone walls built by the quarry men. A quarry man’s shelter, was built into one of the retaining walls and can be found in one of the quiet, sheltered gullies. On the walls of this tunnel hidden behind the ferns and ivy, you can see scrape marks of the tools once used. But this passage is not for the faint hearted as the 5 ton roach stones lining the roof are having to be supported by rusty iron support struts and give the impression that they could come crashing down at any moment.
But tread carefully – these stones are the homes of slow worms, lizards and adders and the nests of little owls.
Look out for the old horse–drawn tramway route which will take you to the Verne Nature Reserve. This path was used by wagons transporting large heavy stone blocks to the Merchants Railway (built 1826), which would then transport the stone to Castletown.
In the far South-West corner of the site, at Easton Lane, is a lime-kiln which has been turned into a private residence. Opposite this lime-kiln is another which is larger and more complete. There is rumoured to be a small stone circle near these buildings, and is only 16 feet across and is made of small stones under 4 foot tall. Unfortunately I could not find this stone circle but maybe you will have better luck!
I also didn’t find any Roman remains but when the area was first quarried, huge numbers of Roman coffins, human bones and pottery were discovered, Some of these finds are now housed in local museums.
Finish of the adventure by heading back into modern times and taking a peek from the top of Kings Barrow at a modern working quarry with impressive views of the rock strata.