The sceleton of some flat Fish

by mercuriuspoliticus

For some reason, it was always trilobites.

By the age of six, I was obsessed with fossils, and while dinosaurs were a big part of that, I was always fondest of trilobites. I remember having a book about prehistoric sea creatures and my eyes were always drawn to what was on the ocean floor rather than the icthyosaurs and plesiosaurs swimming above it. Maybe it was because they were similar to the woodlice I used to like to catch in the garden. By the time I was seven, I had been given a book about the Tudors and Stuarts and suddenly my allegiances shifted. But I’m still fond of trilobites: a geologist friend at university noticed me sneaking a glimpse at her book about them while we were revising in the library, and gave me a plaster cast of one after we finished our finals.

Trilobites, as any six-year old will tell you, are an extinct type of marine arthropod. They appear in the fossil record around 500 million years ago, and died out 250 million years later. The picture above is the fossil of a particular type of trilobite called Oxygiocarella debuchii. This specimen was found at Llandeilo in Glamorgan, by Edward Lhwyd at the end of the seventeenth century.

Lhwyd was the keeper of the Ashmolean Museum and the author of the first English catalogue of fossils: Lithophilacii Britannica ichnographia [EEBO], published in 1699. As part of the research for this book, Lhwyd spent time in Wales, which is where he found his trilobite specimen alongside those of various shells and corals. He wrote to Martin Lister, a member of the Royal Society, about his findings and part of the letter – along with some wonderful etchings like the one above – was published in the Society’s Philosophical Transactions. In his letter Lhwyd described the creature as best he could given the knowledge of the time:

The 15th whereof we found great plenty, must doubtless be referred to the sceleton of some flat Fish.

Although it was not identified as such, this is the first written record of a trilobite. I wonder how many readers of the Philosophical Transactions were as intrigued by the trilobite as I was, aged six. For me – and perhaps for some of Lhwyd’s contemporaries – they hinted at a foreign yet strangely familiar other world, now at a vast distance from us but visible all the same with the tap of a hammer on stone.

This post marks the Royal Society’s decision to make every copy of the Philosophical Transactions freely available online. For more on trilobites, I cannot recommend highly enough Richard Fortey’s wonderful Trilobite! Eyewitness to Evolution (2000), which sets out far more eloquently than I can what makes the trilobite  so alluring.