Apr 20, 2020

Found a rock or fossil? We can help!

The Museum may be closed to visitors, but we are still open online to help you identify your rock and fossil finds remotely.
Category: 2020
Posted by: Sarah

Dug something up in the garden? Dusted something that’s been on your mantelpiece for years?  Found something curious in the gravel? Seen something interesting on your socially-distanced daily exercise outing?   Share your pictures with us, and we’ll do our best to identify them – or pass them on to someone who can.    

Over the course of the year, our Museum staff identify more than 150 rocks and fossils brought in by visitors, or through pictures sent to us.  We can’t always guarantee we can identify something from pictures alone, but we’re happy to try and look forward to hearing from you.  

Share your pictures – and as much information as you can about where your rock came from – on Facebook, Twitter or Instagram, or email them to sedgwickmuseum@cam.ac.uk.   And if you think there aren’t any fossils near you, the flint gravel used for Cambridge paths and borders is ‘full’ of fossils – if you look hard and long enough.  Have a read about it here.

Remember when you send us photographs:

  • Make sure they are clear and in focus
  • Send photographs taken from different angles where possible
  • Use a ruler for scale so that we know how big it is. If you are out and you don't have one with you, use a coin or your shoe beside it instead
  • It is also very useful to know where you found the specimen 

David from Orwell recently approached us with a photograph of a rock he had found on a local walk. We shared pictures of it on our daily Museum team videocall, and everyone pitched in ideas as to what it was.  David was able to send us more detailed high resolution photos, and Douglas, from the Museum team, carried out some further research, consulting with colleagues in the Department of Earth Sciences as well as in the Museum.  

Douglas writes:  

The bulk of the slab is comprised of a mass of broken serpulid worm tubes along with moulds and shells of some other fossils, mostly small bivalves and a few bullet-shaped belemnites. So it is a shelly limestone, what is technically known as a bioclastic limestone. Overall, the rock looks like a shallow marine shoal deposit accumulated by wave and current activity. But the dominant serpulid tubes have probably not travelled very far from where these tube-worms lived. The tubes have not been broken up all that much and many are still retain quite a length of their original curvature. They would be more highly fragmented as a beach or storm deposit.

The age of the limestone is probably Jurassic but could also be Cretaceous because of the presence of the belemnites but see below for some extra information. 

Occurrence: as far as I know and in consultation with colleagues, this is not a local rock but like many exotic slabs found in the fields around Cambridge was probably carried into the region by the glaciers and postglacial rivers during the recent ice ages.

You can more from Douglas’ response here.

Dr Liz Hide
Museum Director

Image credits: David Hope