Access to both has been restricted at the moment on health and safety grounds. Though they're called caves, this isn't strictly true. They are actually mine workings.

Striations on the surface of the limestone

Both are prime examples of open mineral veins. Spanning from three to 10 feet in width. The mineral has been totally extracted from these veins and today we're left with an open chasm to the surface.

Stop at the caves and have a good look around making sure you don't pass the boundaries.

It's an important spot here as we can clearly see striations - scratches made on the rock surface, generally parallel, inscribed by a geologic agent, i.e., glaciers, streams, or faulting on the limestone.

The examples here are perhaps 300 million years old and a result of earth movements. The two pieces of rock have slid horizontally against one another and left scratch marks on the surface.

No doubt you've heard of the San Andreas fault in California USA? Well, this is Derbyshire equivalent.

Lichens pollinate on the rocks' surfaces here, they can be quite misleading, some of them are pale and look similar to crystals whilst others have a rusty tone to them leading you to believe you're seeing iron deposits or fluorspar.

Caves

In the caves you may notice that the limestone is tilting quite steeply revealing the bedding planes - layers the limestone was actually deposited in. These layers may have been originally horizontal on the seabed but now the strata has been tilted by earth movement.

Matlock Bath and Matlock would have certainly been underwater around 330 million years ago - during the Carboniferous period.

This would have been an era of great development for Matlock's limestone but the area would have been totally unrecognisable.

Imagine the Bahamas and you'd have a better idea how the area would look.

If we'd been around at that time we'd have been living in a tropical atoll, a lagoon with beautiful corals and teaming sea life, from the minutest of shell fish to huge sharks.

There'd have been clam like species (brachiopods), sea lilies (crinoids) and other ancient creatures all co existing in this shallow tropical sea.

Eventually the tropical seas became overwhelmed by muds and sands from the north, big river deltas spread sands and silts across the area this was a precursor to the coal measures.

The plant and sea life perished and was eventually buried below the silt.

All of the coal measures and swamps have eroded away from this area and this has again revealed the limestone along with a few fascinating fossils that have been left over.

It's hard to believe that Derbyshire's limestone was actually formed about 15 degrees south of the equator. Over the last 300 million or so years they've slowly travelled to Derbyshire.