Heptonstall
A walk around Heptonstall to look at the rocks, building stones and landscapes of the Calder Valley
more walks | forthcoming events | contact us | return to homepage
The rocks of the Heptonstall area are Upper Carboniferous (Namurian) in age, so they are about 320 million years old.
These rocks were laid down in deltas on the edge of a large continent, with mountains to the north and south. Sands and muds were deposited by rivers in shallow water. Because the continent was close to the equator, the climate was warm and wet so that tropical rain forest flourished. Sometimes plant branches and roots were washed into rivers during floods and became stranded in sandbanks. Their fossils can sometimes be found in sandstone walls or in quarries.
After the sediments were formed, close to sea-
In Hell Hole Quarry a massive outcrop of Lower Kinderscout Grit is exposed in a 20m high quarry face. The site shows cross bedding on an enormous scale, containing beds dipping at approximately 30° within the nearly horizontal bedding planes. These crossbedded sets represent the sandbanks in an enormous river channel, probably equivalent to those of the Mississippi or the Nile rivers, as they flow across a delta into the sea.
Grid Reference
SD 986 276
View of the Upper Calder Valley from above Hell Hole quarry, Heptonstall
The quarry would have been used to extract building stone for local use. The bedding planes and joints provide natural weaknesses which allowed the quarrymen to take off blocks of stone without needing any blasting with dynamite, which would have damaged the stone. The blocks would have been very large and were probably cut into smaller sections, using plugs and feathers. They would have been transported down to the valley in carts along the track at the base of the quarry.
Heptonstall shows the use of the building stones very well, although we can’t be sure that the stone here came from Hell Hole Quarry, as there are other smaller quarries nearby. The biggest blocks could be sawn into lintels and mullions for doors or windows, while more finely bedded blocks were used for flag stones or roofs for outhouses. The thinnest flags were split for roofing. Broken stone was used for field walls and any spare stone could be crushed to be put on field tracks or lanes.
Bedding planes
Cross-
Building stone
Headstones
Lintels and mullions
Roof slates
Heptonstall churchyard to show the use of local sandstones