Saturday, 24 July 2010

Fossil Collecting: Fun, but not always fruitful.

Within the last couple of weeks I have had a couple of fossil collecting trips which have varied a lot. Both were enjoyable but couldn't be more different. One involved lots of people of a wide range of ages; the other was just myself and a friend. The first involved me searching through shale for fossils on a beach; the other had me looking at a limestone/dolomite cliff risking being nettled.

Runswick Bay - 15/07/2010

The first trip, on the 15th of July, was organised by Doncaster Museum and led by Dean Lomax of Palaeocritti. There were around 40 of us altogether, ranging from young children to the elderly. We went by coach to Runswick Bay, a well known fossil collecting locality north of Whitby, as can be seen on the map below.

It is not a place I had been before, though I knew the rocks would be of Jurassic age. There is also the potential for finding some quite random fossils, brought down to the bay by glacial erratics, but it is often best to stick to the shale in order to know what time period your collected fossil is from. We arrived at the bay in the morning to find that coaches could not get down the hill, forcing us to walk down a steep hill, so of course it rained on us. One thing I did find interesting on the trip down the hill was the paving slabs in the driveway of a house; they contained pseudofossils formed when magnesium oxide gets into cracks in limestone.The picture below shows a view of the bay:
When we were collecting fossils the weather cleared up. Some of the children started finding fossils straight away, their eyes seemed almost unnaturally attuned to spotting fossils. Rocks were repeatedly overturned, shale smashed and everyone went along at their own pace. It was one of those trips where everyone found fossils. It was very easy to come across casts of ammonites and bivalves, devil's toenails (Gryphaea) were common, along with occasional belemnites. One of the best finds was an ammonite mass mortality (Harpoceras I believe) and also a potential crustacean part (I reckon a crab) and some possible fish bones. I was also a little jealous when Dean found a chunk of rock with ripple marks; I do like ripples (and really should get the picture of me at Durdle Door next to some huge, uplifted ripples). Below is a picture of the group fossil hunting, you can see me on the left with my shorts, typical hat and big boots:
My own finds were nothing special (though all fossils are special in their own way) but then I really went just for the enjoyment of it. I have some ammonite casts, lots of bivalves (I always find bivalves) and a couple of belemnites.

South Elmsall - 20/07/2010

My trip to South Elmsall quarry was very different. South Elmsall is to the north of Doncaster towards Wakefield and happens to be just down the road from where a couple of friends of mine live. Whilst researching the geology of the area I found out that there might be fossils in South Elmsall Quarry from a paper I found online. From what I gathered from the paper, there was the possibility of finding more like those I have found in Conisbrough, plus a few others not found here. My friends who live near South Elmsall had asked me to come help them with some stuff, so I mentioned the possibility of me heading to the quarry at some point, to which they responded by saying I could take their youngest son out with me as he has just finished GCSEs and doesn't have a lot to do. So on the Tuesday we set out for about an hour to explore, with this map to guide us:

It was actually very easy to find and thankfully a lot of the cliff was exposed; a previous search on Google Maps made it look like the trip would be futile. The first thing you see when you approach the cliff are some excellent examples of stromatolitic domes. Formed by algae building up sediment, these domes resemble a lettuce in cross section. I did not have a camera with me, so sadly I could not take pictures, but here is an image from the paper:

This image is not particularly good, or at least it does not compare to how I remember them. There is no sense of scale (we are always told to make sure there is something to reference for scale at uni) and the typical graffiti at the bottom could be any size really. The stromatolites are worth looking at, so at some point I will go back and take some proper pictures. I looked around as much of the rocks as possible and found no fossils at all. No Liebea squamosa, no Dielasma elongatum. The paper had me thinking I would find many bivalves (Liebea, Bakevellia, Permophorus and Schizodus) along with bryozoa (Acanthocladia) but I should have been realistic, after all, many of these are meant to be in Conisbrough too but I have not yet found them. I did, however, find some casts which appear to have been Bakevellia binneyi as they were roughly the right size and shape, plus there were more than one of them. There was nothing I could take home with me, only the image of stromatolites and bivalve casts in my head. I intend to return, at least to take pictures, but I may also find something.

These two trips make an interesting contrast. The first had me finding things easily, coming away with a heavier bag even though I had emptied it of my lunch. The second had me coming back empty handed, which I don't mind too much as it is good experience; palaeontologists have to get used to disappointment as many of the best finds seem to be down to luck. In my opinion, going out and failing to find something to take home is more worthwhile than not going at all.

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