I volunteered for the Oxford University Museum of Natural History yesterday on one of their Dino Days that they do for Year 7s. I wanted to remind myself what secondary school students were like, plus I’m fond of dinosaurs. It was a great day.

I was helping with casting dinosaur footprints and other fossil casts with plaster of paris. One of the conservators had made silicon moulds for the job, and the kids had to follow instructions to mix the plaster and pour it into the moulds. While it hardened, they found out a bit more about trace and true form fossils.

I’m particularly fond of trace fossils, from coprolites (fossilised faeces) to footprints to skin impressions. I wrote a block of work on trace fossils, the study of which is called ichnology, for the Hamilton Trust. While the conditions for fossilisation for both true form and trace fossils are similar, there is so much more potential for greater numbers of trace fossils than true form, since every single dinosaur could have left thousands of footprints or specimens of faeces behind, but only one body.

 

A large coprolite (fossilized feces or dinosaur poop) from South Carolina, USA..jpg
A large coprolite (fossilized feces or dinosaur poop) from South Carolina, USA.” by PoozeumOwn work. Licensed under CC BY-SA 4.0 via Commons.

One of my favourite finds for the block I wrote was a quarry in Bolivia where thousands of dinosaur footprints have been found. Due to the movement of the earth’s crust since the time of the dinosaurs, these now appear to be walking vertically up the wall.

Dinosaur tracks in Bolivia 1.jpg
Dinosaur tracks in Bolivia 1” by Jerry Daykin from Cambridge, United KingdomFlickr. Licensed under CC BY 2.0 via Commons.

I also like this one where the dinosaur had clearly sat down and then moved away again, found at a farm in Utah.

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Squatting dinosaur tracks at Johnson’s Farm in St George, by Nancy Carruthers, Utah Geological Survey

Early and modern humans have also left tracks (though not in the same strata as dinosaurs as some would have you believe) like the famous ones at Laetoli in Tanzania (probably 3.7 million years old and belonging to Australopithecus afarensis), but also at Happisburgh in the UK (about 800,000 years old and possibly Homo antecessor) and modern humans, Homo sapiens, around 7000 years ago at Monte Hermoso in Argentina. What better way to get children to engage with what these footprints can tell us (height, gait, speed) than by getting them to make dinosaur feet, dip them in paint and run across paper with them, or make their own footprints in wet sand and fill them in with casting material?

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