Tag Archives: fossil

Identification – Ammonite in sandstone

One of the most interesting parts of working in museums is helping people discover something new (and I usually learn something new myself). A really important way for museums to do their job as a welcoming public source of information is by identifying mystery objects that you might find on a walk, on a seaside holiday or even in your garden or attic.
Anyone can bring in an item for us to identify, for free, and you should have an answer within a few weeks. It might look a bit like this:

Ammonite in sandstone

This piece of stone is a Jurassic fine-grained sandstone or sandy limestone, which may be from the Lias Group rock unit found on the Dorset coast, although it has a sandier appearance and rougher texture than the rocks usually found in this formation. If it is from the Dorset Lias formation, the rock is roughly 195 to 200 million years old, and the fossils it contains would be a species of Promicroceras ammonite, which are common along the Dorset coast.

Fossil of a Promicroceras ammonite.
Image: Ammojoe CC BY-SA 3.0 (Wikimedia Commons)

The bristleworm, Polydora ciliata. Image: Yale Peabody Museum of Natural History [CC0] (Wikimedia Commons)

 

 

 

 

 

 

The surface pattern of pores in the rock was made much more recently. They were probably made by a species of Polydora worm, probably Polydora ciliata. P. ciliata is a small, rock- or shell-boring worm which can grow up to 30mm (1 1/8 in.) long, and is also known as a bristleworm.

P. ciliata burrows in stone. Image: Rosser1954 CC BY-SA 3.0 (Wikimedia Commons)

Bristleworms are thought to burrow into rock or shell by scraping away at the surface using specialised bristles on the fifth segment of its body, although it may also secrete chemicals such as weak acid to help. It digs a U-shaped burrow, which appears on rocks as distinctive small slots or a ‘sunglasses’ shape.

 – James Lumbard, Natural Sciences Officer.

 

A bit behind the scenes

An update from James Lumbard, Natural Sciences Officer.

The Geology Gallery received a lot of attention in the run-up to the festive period thanks in no small part to the help provided by Cali, the latest addition to the natural sciences volunteer team. After a short training session in how to carefully clean specimens using a conservation vac and a paintbrush, we were away, and have already cleaned around half of the objects on display at the time of writing. It should be a fairly quick job to finish the rest of the objects in the ‘table-top’ display cases, leaving only a dozen or so in wall-mounted cases. This is part of regular ‘deep cleans’ that help care for museum objects, and will help us double-check and update the information we hold about each object. Many museums are also ‘Accredited’ which means that they uphold certain national standards of collection care, and this work contributes to Saffron Walden Museum maintaining its Accredited status year-on-year. Meanwhile, the photos we take can be used for everything from social media to encouraging researchers to visit the collection.

Fossil ammonite found in Saffron Walden. 150-200 million y.o.

At the start of December I visited the Essex Field Club’s (EFC) annual exhibition and social at Wat Tyler Country Park, near Basildon. The EFC is a volunteer-run society of amateurs and professionals who compile and look after a county-wide database of the wildlife and geology of Essex. The club’s secretary, Fiona Hutchings, very kindly introduced me to members from each specialty so I could speak to them about the natural sciences exhibition this summer, called Take Away the Walls. My plan is to hold a museum-based exhibition showcasing the wildlife of north-west Essex, and to run activities bringing together wildlife organisations and community groups across Uttlesford to help people enjoy the outdoors in new ways that will benefit their own health, and the health of the local environment. The exhibition and activities will really start to take shape behind the scenes soon, so keep your eyes peeled for more updates in the coming months.

Fossil bryozoan in flint. Tiny bryozoa live in coral-like colonies (above), but are much more complex internally.

At the end of this month I will be attending a short training seminar entitled ‘Finding Funds for Fossils, Ferns and Flamingos’, hosted by the Natural Sciences Collections Association (NatSCA) at the World Museum, Liverpool. NatSCA are a nationwide ‘subject-specialist network’ of museum professionals working in the natural sciences who have an active programme of meetings, training courses and conferences throughout the year. This particular event is all about how to successfully attract funding and support to care for and promote natural sciences collections in museums, and I look forward to putting my new-found knowledge into use to benefit the tens of thousands of natural sciences specimens at Saffron Walden Museum.

Object of the Month -September 2018

September’s Object of the Month is a collection of fossilised teeth chosen by James Lumbard, Natural Sciences Officer.

These fossilised teeth come from the extinct fish Ptychodus (pronounced tie-co-duss) which lived across the Americas, Europe and Asia. They are closely related to modern sharks and rays, but may not have been direct ancestors. Some species grew up to 10 metres long, feeding on the large shellfish that existed during the Cretaceous period, 66–145 million years ago. Although they had similar diet and teeth to modern rays, they looked more like modern nurse sharks, which cruise the seabed for small fish and shellfish.

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