Land Manager's Diary: Read it here>

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We're fortunate this week to be able to feature a guest article from our wonderful and knowledgeable volunteer Mary Breakell. Hands-on experience and an eye for detail inform Mary's blog as we get to learn more about the carboniferous limestone used for our dry stone walls in this area and the abundance of fossils that remind us of its ancient origin. If you'd like to join us on any of our workparties, you'll find the schedule of activities and booking facilities at this link>

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A Blog by Mary Breakell

I am not a geologist or a professional waller. I retired 9 years ago and after doing the Dry Stone Walling Association's beginners' course in 2014, I began joining Friends of the Lake District work parties to help repair walls at Mazonwath, on Little Asby Common. Tony, my husband, had been walling at Mazonwath for a long time before I retired  and his descriptions of the area whetted my appetite. 

Anyone who has walled at Mazonwath will know all about the challenges presented by the walling stone there.  The  stones range in size from no thicker than dinner plates to stones as big as dining tables. Walling is heavily influenced by geology because the type of rock shapes the walling style. 

This area is carboniferous limestone. This sedimentary rock is especially susceptible to weathering bywater and frost which makes the stone often too easy to split- hence the dinner plates. Weathering can also make limestone very fragile so that what seems to be a substantial stone disintegrates into slivers in the blink of an eye. 

Mazonwath is adjacent to the Asby Scar Nature Reserve and arguably the best limestone pavements in the country, though far less well known than Malham. What is intriguing is that there is a geological Asbian Age- (330-339 million years ago) in carboniferous limestone which derives its name from Little Asby. In this period Northern Britain lay close to the equator with a climate that has been described as 'monsoonal'.  The limestone was created from the fragments of shells of sea creatures that inhabited this tropical sea. 

Almost every walling session at Mazonwath has revealed fossils, some among walling stone and some hiding ignominiously among hearting - the small stone we use to fill the centre of our walls.. My most exciting find was in September 2018 when I found a beautiful piece of coral - a fan coral. We put the stone back in the wall, where it came from and where it had been for at least 150 years. After all this is part of the landscape and like flora and fauna should not be removed and we are quite short of walling stone at Mazonwath.

Pictured (below) Fan coral

Pictured (below) I have found more examples of coral, though nothing as well preserved as the example above.

Pictured (below) One day we found an ammonite which somehow looked a little sinister

Ammonites were found in the sea between 240 million and 65 million years ago (the Jurassic period to the Cretaceous period) and became extinct at the same time as the dinosaurs. The name comes from the Greek ram horned god Ammon and were predators and part of the cephalopod group which today includes are squid, cuttlefish and octopus. So Jean's feeling that our fossil was not entirely friendly was right, though their main food was plankton. Here is an excellent geological study by the British Geological Survey.