Looking back at the hill, you’ll see why I recommended taking that detour to the right; the well-worn way coming down is so steep it requires rock climbing skills. And what a dramatically sudden end to those slopes which are indeed like the plates on the back of a gigantic stegosaurus.

From our viewpoint on the flat valley floor, with a little imagination, it feels like we could be standing on a sea bed, looking up at a coral reef. Well, around 350 million years ago, during the Carboniferous period that would have been precisely where we were. During this period much of Britain was covered by warm, tropical seas as the part of the Earth’s crust that we now know as Europe was actually located very near to the Equator.
The term for these limestone hills is reef knolls. They were formed on the ancient sea bed as layers of tiny dead sea creatures, such as early molluscs and sponges, built up over millions of years to form limestone mounds.
This area of Dovedale sits at the junction between this harder limestone and softer, clay-like shale deposits which formed in the shallower parts of the sea. Over time, as the softer surrounding shale rocks have worn away these jagged limestone hills have been left behind.
Of course, we would not have needed walking boots, but a diving suit or mini-submarine to explore the undersea world back then. Today we can only imagine such buoyant luxury as a warm tropical sea to float in, as we turn around to face the challenge of the climb up Chrome Hill.
Next, walk along the minor road a very short way towards the cattle grid and sign which reads, HORSE DRAWN VEHICLES AND ANIMALS. This is the start of the concessionary path to Chrome Hill. Make your way to the top via the well-worn route, then over the summit a short way, to find the rock arch, just to the right of the path.
This trail was originally developed by Simon Corble for the Royal Geographical Society’s Discovering Britain.
Simon Corble is a theatre director, playwright and actor based in Derbyshire’s Peak District, is passionate about the countryside and discovering the hidden secrets of the natural world.