Most of the fossils found in the area are of the Carboniferous period, which lasted from about 360 million years ago to 290 mya. During this time the land we now call Britain was on the equator and was an area where rivers washed into a warm shallow sea. In fact the West Pennine Moors and Winter Hill were at that time covered in tropical swamps that were repeatedly flooded by rising and falling sea levels.
So we have a repeating sequence of heavy vegetation and muddy swamps with periods of time when the area was covered by tidal river deltas.
We have Carboniferous plant fossils from the times that the area was above sea level and thin “Marine Bands” of marine fossils from when the area was under the sea.
The ground above the bedrock in much of the area is based on glacial deposits and much of the soil is crammed with pebbles of rock from different areas that was transported here in the ice of glaciers and left behind where they melted.
These rocks can contain fossils that aren’t natural to this area. But they’re still fossils and still here by ‘natural’ processes - so find them too.
No there aren’t fossil fairies going round planting stuff for us to find, at least not that I know of. But there’s plenty of gravel paths, building materials and boulders that have been brought into the area, and these can contain fossils too.
There’s and area just below the castle walls on the bank of Lower Rivington Reservoir that was reinforced perhaps in the early nineties by big dumps of quite sizable chunks of limestone and these contain tons of marine fossils.
As a general rule, if you find a bunch of different rock types that aren’t native to the area together, they’re probably glacial erratics. If you find a lot of same rock types that aren’t native to the area together then it’s probably be brought in for construction or dumped there.
Fossil Lycopsid Roots image by munki-boy
The fossils we usually find in the local gritstone are of Carboniferous plants or the ancestors of trees
There are several Marine Bands in the area, layers of shale that represent areas where a shallow sea invaded something like a large river delta swamp
Non-native fossils found in glacial erratics deposited in the West Pennine Moors area
Fossil bearing limestone transported to the West Pennine Moors by glacier
