Tuesday, 14 April 2009


When people say you can't polish a turd, don't believe them.

Coprolites are fossil dung. The one above is from a turtle. Probably quite a big turtle. I get asked how you can tell which animal 'laid' it. It's not always possible, but at times a direct comparison can be with recent examples. Preferably not that recent. In other instances, clues can often be found in the stratigraphy. It's usually possible to piece together a reasonable understanding of the palaeoenvironment; where and how the animal was living. Also, sections can be made, allowing a look inside the jobby. Exciting work.

A site in Moab, Utah provides a great deal of this stuff, and very often you can see little cross sections of undigested plant material in the polished surface. Found amongst the coprolites are the occasional gastrolith, or gizzard stone. Like some animals today, many dinosaurs ingested pebbles to help them break down tough plants in their gut. I wouldn't suggest you eat a handful of gravel before your tea, but it was very helpful for some of the sauropods of the Jurassic.

Much of the plant material in these coprolites is preserved as a vibrant red jasper, and the most colourful stuff is graded out and used to make jewellery. A few years ago there was a bit of a Hollywood craze for wearing coprolite jewellery. Didn't really catch on here, unfortunately.


Christopher Walker said...

are you suggesting people in California have sh*t taste?

Matt Dale said...

California's a big place.

Christopher Walker said...

A friend came round at the weekend with their seven year old kid. He was fascinated by dinosaurs and fossils and wanted to know more. Given he probably has more knowledge than I, any ideas for activities I could do with him when I babysit him this weekend to further his interest in this area?

Matt Dale said...

Find out a little about the local geology. It's usually not far to the nearest fossil locality. A ranger service, nearby museum or university may well be able to point you in the right direction.