On the 1st August, UKAFH members gathered at Caistor Quarry in Caistor st Edmund, a village just south of Norwich in Norfolk. Our hosts, Needham Chalks Ltd, kindly granted us permission to visit their working quarry to study the geology and search for fossils found within the exposed rocks. This was the first club hunt to take place since the outbreak of coronavirus and we were rewarded with a hot, sunny day as we welcomed friends old and new to our socially-distanced field trip!
The working quarry produces thousands of tonnes of ground chalk, lump chalk and flint per annum and sand derived from the Norwich Crag and Pleistocene gravels are also commercially extracted from the surface before the extraction of chalk begins. Generally the Pleistocene exposures at this location are difficult to access as we are within the steep quarry walls but in any case the chalk is the more interesting and productive when it comes to fossils.
The chalk forms part of the Beeston Chalk Member, some of the earliest chalk exposed in the UK of Late Campanian age at circa 80 million years old. Importantly, this chalk member is not exposed on the UK coastline and so access to it can only be achieved via inland sites such as Caistor Quarry. The chalk formed at the bottom of a warm, relatively deep sea that was inhabited by great numbers of microscopic coccolithophores – phytoplankton whose tiny calcite platelets, called coccoliths formed the striking white calcium carbonate sediment. Fortunately for us the Beeston Chalk Member is particularly fossiliferous, with belemnites, brachiopods, echinoids and fish remains being frequently found.
We began with a geological explanation and description of likely finds provided by Sam Caethoven, along with a health and safety briefing, before heading into the quarry. The quarry was in operation during our visit so it was vital we kept away from the large machinery and remained as a group throughout the hunt, however the work today was focused on sand extraction so we had the entirety of the chalk pits to examine. Since our last visit in 2017 the quarry landscape had changed significantly so we saw different exposures compared to our previous visit. There were also large piles of loose material to go through on the floor of one pit. Certainly the number and type of finds made by the group were very different to those found on the previous occasion.
We were in many ways lucky with the weather, a beautiful warm and sunny Norfolk day, without the unrelenting heat and high temperatures experienced earlier in the week, however within the quarry we were very exposed so plenty of water and sunscreen was essential and the bright sunshine reflecting off the bright white chalk was glaring, making it harder to spot fossils than might otherwise be the case.
The finds began with a large multi-block of echinoids in flint made by Sam Caethoven. Although the echinocorys echinoids were unextractable from the block and somewhat worn it still made an attractive piece, even if only to serve as a doorstop!
On our previous visit echinoids were plentiful however on this occasion we wound them much harder to come by. However some beautiful specimens were founds, primarily in flint blocks, by Dave Clark, Tracey Chapman and Andrew Bourke.
One fossil the group found in abundance was belemnites, a squid-like cephalopod whose guard is preserved as a glossy brown bullet-shape. Some fine examples, including complete specimens were found, with some displaying entobia, the fine, web-like traces left by the presence of boring sponges. Brachiopods and bivanves were also found.
Since the quarry was dug deeper than our previous visit we were fortunate to find several examples of fish remains from the lower beds. These appear as glassy, caramel-coloured scales preserved in the chalk. Several members found fish scales and partial fish, with at least one find including articulated vertebrae.
It was a glorious day to be out fossiling and everyone appreciated the opportunity to spend the day doing something they loved along with like-minded people. Lockdown has been hard on many of us and it was a great pleasure to be safely outdoors seeing friendly faces and catching up, albeit at safe distances. Thankfully no-one wants to be fossil hunting in each others’ spaces anyway and we had a huge quarry all to ourselves to space out in. Thank you to the awesome group who attended and a huge thank you goes to Needham Chalks Ltd who let us investigate their quarry.