Saturday, 21 December 2013

Trip report, 14/12/2013 The Geology Trail, Brown’s Folly Nature Reserve

A group of 32 people, plus and minus their cars, gathered at the entrance to Brown’s Folly nature reserve near the top of Farleigh Rise, waiting to be entranced by Elizabeth Devon’s introduction to the Geology Trail that has been marked out through the woods and grassland with blue-topped posts. Elizabeth is one of those rare educators who bring her subject enthusiastically to life by setting the scene of the ‘big picture’ within which the details of the smaller scale, analytical view can be appreciated and understood. She laid out a magnificent coloured wall chart for us to view, on which were mapped out the environmental circumstances in which the surface rocks of different regions of Britain and Ireland were formed. This gave us the awareness of how to look, where to look, what to look for and why we would expect to find it there, which is so crucial to well-informed – as distinct from haphazard - naturalistic exploration and enquiry.
Thus prepared, we set out first of all along the top of the reserve to Site I, possibly an old adit mine whose roof has collapsed and been cleared. Here we were able closely to examine the layer of cream coloured Bath Oolite that was mined for use in the buildings in and around Bath. Informed by Elizabeth’s introduction, we were able to examine the tiny spherical ooids – or hollows where they had been – in full knowledge of how they were formed. Above this was the hard ‘Roof Bed’, which serves as a very clear marker band in rocks seen elsewhere around the reserve.
We continued around the trail in mild, mostly dry and at times breezy conditions, visiting the different sites at which we were able to observe such features as current-bedding – which gives some exposed rocks a striking ridged and grooved appearance, and a variety of fossils. Amongst the most exciting of the latter was a sample of fossil coral, which drew gasps of admiration from people as they took a close look at it with a hand lens.
Back at the car park, Elizabeth handed out some free wall charts and took a small party who were prepared to delay lunch, to see some fascinating fossil burrows through rocks near there. We left richly informed and looking forward to future visits to Brown’s Folly reserve well-prepared to understand the above ground distribution of surface fauna, flora and mycota in the context of what lies below ground – and how, why, where and in what circumstances it got there.

Alan Rayner

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