The Tower of London

A view of the Tower of London in 2009

When I first started this Blog, back in 2014, it reflected my interests in teaching English, learning other European languages and Geotourism and, by the end of 2016, I had explored as many geological sites, castles, cathedrals, mediaeval churches and other notable historic buildings as I could – travelling entirely by public transport from Treeton.

On the way to the public entrance to the Tower of London

Having finished my tour at Rowsley in the Peak District National Park, my next day out was to explore the Tower of London. I had last visited this tourist attraction as a child but, while working in the building restoration industry, I had passed by it enough times to know that the bulk of its curtain walls are built from Kentish ragstone – a siliceous limestone of Cretaceous age.

A geological map of the area around Maidstone

First extracted from the Lower Greensand in the area around Maidstone by the Romans - and with fragments of the city wall still preserved - I had also seen Kentish ragstone as rubble walling in a few churches and other historic buildings when living in South London; however, I have not yet explored its geology in the natural landscape, visited any quarries or had any cause to further investigate this particular building stone in any detail.

A section of the remaining Roman Wall in London

Its hard and intractable nature, which makes it unsuitable for ashlar or dressings, and its grey/brown colouration with a green tinge - due to the presence of the mineral glauconite - is quite distinctive. As an introduction to Kentish ragstone in London, there is no better place than the Tower of London from which to start.

A plan of the Tower of London

With only a simple plan to lead me around, and with little knowledge of the construction history since the White Tower was built by William the Conquerer, I then proceeded to spend 3 hours exploring this magnificent castle – encountering many other building stones along the way.

A view of the Tower of London in 2009