100 Great Geosites

100 Great Geosites nomination: Eglwyseg Escarpment

A 100 Great Geosites nomination from Raymond Roberts, Senior Geologist at Natural Resources Wales

I could easily have chosen a dozen or so sites for my favourite geosites. In the end I chose my local one – The Eglwyseg Escarpment.

Eglwyseg Escarpment

Eglwyseg Escarpment from Dinas Bran

It doesn’t matter if you see it from the A5, the Horseshoe Pass or look across the Dee Valley from the Berwyn Mountains, every glimpse of the Eglwyseg Escarpment looks fantastic. Stretching for nearly 10 kilometres and rising high above the valley floor, it has to be one of the most dramatic landscapes in Wales. And to make it even more special it is a fantastic place for geology.

Eglwyseg Escarpment 2

Cliffs and screes dominate the landscape

The Eglwyseg has something for all. I come for walks with my family, pappose and all, some come for the view or the climbing, others for geology or geography fieldtrips, and many just pass through as they follow Offa’s Dyke. Whatever the reason, it is the geology that has brought them.

Geology students, walkers and climbers enjoy the geology

Geology students, walkers and climbers enjoy the geology

The main escarpment rises in a series of steps over 450m, and includes one of the finest exposures of late Dinantian limestones in Wales. Such a thick sequence shows the different styles of Dinantian cyclicity, whilst the 10km or so length of escarpment provides an opportunity to study the lateral variation in sedimentation.

A bonus feature of Eglwyseg are the screes – millions of limestone fragments which have collected at the foot of the cliffs since the end of the last Ice Age. One of the wonders of Wales, the Eglwyseg screes are probably the best in the UK.

eglwyseg limestone cliffs

Dramatic limestone cliffs and screes

eglwyseg oolitic limestone

Cross-bedded oolitic limestone



The geology and geomorphology of the Eglwyseg allows research at the highest level. But easily accessible exposures, both dip & strike sections, and fossils makes Eglwyseg an outdoor classroom for any age. My passion for geology started as a child when I started finding fossil plants in some of the old coal tips of South Wales, and I’m sure a visit to the Eglwyseg has fired the imagination of many children, and adults!

  • Nominations for the 100 Great Geosites project are closing on Friday 18th July – but we would still love to receive blog posts! If you would like to write a blog about your favourite geosite, write to us at 100geosites@geolsoc.org.uk.  Visit our Flickr page to see the nominations so far! And stay tuned for information about how to vote for your favourites from the list of nominations…


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