The uplands of Lancashire consist mainly of carboniferous rocks, whilst those of the plain are tuarssic. The Rossendale anticline lies West of the main Pennine Axis and is adjacent to the north – east trending Pendle range. They are separated by the Burnley syncline in which Rishton is situated.
The underlying rocks of the Rishton area are carboniferous coal measures with more recent deposits laid down on top of them.
The highest land in Rishton, the ridge to the North and North West, is formed of millstone grit and reaches a height of 750 ft. This is the only place in Rishton where millstone grit appears at the surface.
At its lowest point, along the River Hyndburn it measures below 250 feet, a height difference of 500 feet.
The coal measures found in Rishton are middle and lower coal measures and the middle coal measures outcrop along the Hyndburn River. This river has also deposited alluvium along its banks.
There are two distinct types of glacial drift to be found in Lancashire; the Ribblesdale and the North Western drift. The Ribblesdale drift is characterised by abundant limestone boulders. The Northwest drift is composed of reddish brown clay and contains erratic from the Lake District and Southern uplands of Scotland.
Rishton is situated at a stage in the retreat of the ice that witnessed the complete severance of the Ribblesdale ice sheet from the North West one. The Cliviger Gorge was no longer in operation and a large lake covered the Accrington district. The glacial drift found in Rishton is the North West drift that is though to be a product of the Irish Sea ice, covering South Lancashire. The Irish Sea ice sheet was more extensive than the Ribblesdale one and forced the latter to retreat eastwards. Boulder clay has covered most of the underlying rocks in Rishton.
The town of Rishton itself has been built on glacial sands and gravels. These sands and gravels extend approximately from the reservoir in the West to the river Hyndburn and from the Blackburn to Great Harwood branch railway line in the North to the Blackburn to Accrington railway line in the South.
A North east Lancashire Town by Marian Sleigh