Ancient Wharfedale corals

My stepson and his family have been staying in the Peak District and, along with lots of photos of bleak but beautiful scenery, came one taken in Treak Cliff Cavern. It showed a rectangle of rock stuffed full of strange shapes: the fossilized remains of crinoids, marine creatures also known as sea lilies.

Then, a few days later, a friend brought me a stone, found locally. It was about the size of a loaf of bread, and it too was full of strange raised shapes. Did I know anything about fossils? Well, not really, but, as a member of the WNS, I know someone who does. Our expert came along armed with camera and lens and before long a whole world, a very ancient one, opened up before me.

First we established that the rock passed to me was Carboniferous limestone. We did this by dripping a tiny spot of vinegar onto the stone; the vinegar (acid) interacted with the stone (alkali) and gave a satisfying little fizz. Oh, the wonders of Chemistry! Next for the lumps and bumps: one was about five inches long, slightly curved and with a series of ridges crossing it. In outline it looked like a slightly rumpled rope ladder. On the other sides of the stone were circles with crimped edges resembling the rims of seashells. These were all different sizes and interspersed with smaller rectangular and cone shapes. All were examined closely – and identified. What had been found in a local garden was a collection of fossilized rugose (horn-shaped) corals. The ladder-like object was a cross section and the circles outlined the upper ends from which the coral polyps would emerge when the creatures were alive.

And here’s the amazing bit. They were living here, in Wharfedale 330,000,000 years ago. Then the whole area was covered with a warm shallow sea, and our corals would be sharing their world with a whole lot of other corals – simple and compound – with sea lilies like those in Derbyshire and with fish with very sharp teeth. Suddenly my concept of time, marked by calendar, birthdays, anniversaries, even the two centuries of my A Level History syllabus, shrinks to an eye-blink against the vastness of geological time. Familiar Wharfedale, as defined by its scenery, seasons, and ecology, shifts and mutates.

Jenny Dixon