Edited by Douglas Palmer and Barrie Rickards
A few months ago, I dropped my son off at Glasgow University and, on the way back, resolved to visit Dob’s Linn in Dumfries and Galloway. As readers may know, this is a classic geological site, not just in the UK, but also across the world. It contains the golden spike of the Global Boundary Stratotype Section and Point (GSSP) marking the boundary between the Ordovician and Silurian periods. And Dob’s Linn was also instrumental in Lapworth’s explanation of the complexity of Silurian deposits in the area and the efficacy of using graptolites as index fossils during the Palaeozoic.
Needless to say, I found wonderful graptolites, about which I knew very little. Therefore, I dug out my copy of Graptolites by Douglas Palmer and Barrie Rickards (and bought Graptolite Paleobiology) to find out more. It was published in 2001, but is still a wonderful book, especially for its black and white photographs.
As it explains, graptolites lived in the earth’s oceans from 540 million years ago to 320 million years ago, when they became extinct. For most of that time they dominated the upper layers of the ocean in tropical regions as the earth’s first large zooplankton. They varied from a few millimetres in length to more than a metre, and existed in their billions, and their skeletons are preserved today in vast numbers in varied strata in every continent except Antarctica.
As mentioned above, because of their diversity, they are a powerful correlative tool and units of time of much less than a million years are identifiable. Therefore, within individual rock sequences, evolutionary changes can be studied, which makes them of prime importance to economic geologists.
The book provides a summary of the state of knowledge (at that time) relating to graptolites, and the specialists, who contribute to the book, also address the biological questions raised by these fossils, and provide pointers for further research.
As such, it is nice little introduction to graptolites. If you want a more academic (and up-to-date) book on the subject, try Graptolite Paleobiology.
At the time of writing, Barrie Rickards was Reader in Palaeobiology at the University of Cambridge, and curator of the Sedgwick Museum of Geology. He went on to become Emeritus Professor in Palaeontology and Biostratigraphy at the Department of Earth Sciences at Cambridge University and Life Fellow of Emmanuel College. However, he is best known for his work on graptolites. Douglas Palmer was a freelance geologist and writer.
Graptolites: Fossils illustrated, by Douglas Palmer and Barrie Rickards, The Boydell Press, Woodbridge (2001), 182 pages (hardback), ISBN : 978-08511526-2-2