The Origin of Cotswold Stone

It is often said that the most striking distinguishing characteristic of the beautiful Cotswold region in England is the prevalence of the beautiful light-coloured limestone buildings, referred to locally as Cotswold Stone. The structures that are built in Cotswold stone, some of which date back before to before the Saxon period, give off an almost honey-toned appearance, lending itself well to the picture-perfect quality of light that these historic Cotswold villages are so known for. Over the years, There is much evidence of this golden glow in both art and literature pertaining to this region of England, solidifying its position as a trademark for the bucolic hillsides of this South Midland region in which they stand.

Cotswold stone is a type of limestone; a variety of sedimentary rock that is usually composed of calcium carbonate derived from the skeletal remains of long-buried marine organisms. Cotswold Stone is generally quarried from the hillsides surrounding this South Midland region, often referred to as the “Cotswold Edge”.  What makes Cotswold limestone so unique, in addition to the aforementioned distinctive golden colour, is its granular texture. In geological terms, this granular texture is referred to as having an oolite appearance. The term is derived from the Hellenic word ooion, which means egg. Indeed, when one looks closely at an oolite surface, the appearance of a cluster of small, egg-like bumps on the surface is readily apparent. Each of these individual bumps represents the calcified remains of an individual ooid.

Usually found in inland lakes or areas of warm, agitated tidal seawater, these layers of ooid limestone began with something as simple as a single shell. Tidal currents would carry layer upon layer of shell fragments around the seabed, and they would build-up and collect in various locations. The Cotswold Stone that we know today is thought to have been created by this very process during the Jurassic period, and is spread out under the surface of the Cotswold Hills in a sand dune-like configuration.

Limestone such as the Cotswold Stone has been a very popular building material for a very long time; even The Great Pyramids of the Giza Acropolis are constructed from a form of limestone. One of the reasons for this long-standing affinity for building with limestone is down to availability. Because limestone originated with the aforementioned marine life, it is abundant. After all, at one point, most of the earth’s surface is or was covered  with water. In addition to its availability, limestone is also quite a porous stone, making at rather soft and easy to cut into manageable-sized blocks. Early on, there were many limestone deposits that were readily available in easy to access surface deposits. This made it quite an attractive building material during the middle ages, as evidenced by the Cotswold villages that are nearly uniformly limestone.

Despite its popularity, with industrial advancement came the realisation that limestone was a very heavy and cumbersome material to work with, accounting for why after the industrial revolution, limestone fell out of vogue in favour of more modern materials.